diff --git a/.idea/discord.xml b/.idea/discord.xml
new file mode 100644
index 000000000..d8e956166
--- /dev/null
+++ b/.idea/discord.xml
@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="DiscordProjectSettings">
+    <option name="show" value="PROJECT_FILES" />
+    <option name="description" value="" />
+  </component>
+</project>
\ No newline at end of file
diff --git a/Cargo.lock b/Cargo.lock
index f88a687a4..84bfe7104 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1,5 +1,7 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
+version = 3
+
 [[package]]
 name = "adler"
 version = "1.0.2"
@@ -123,6 +125,22 @@ dependencies = [
  "cfg-if",
 ]
 
+[[package]]
+name = "daedalus"
+version = "0.1.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "667dec20054908ee40916a3fd8ea5bfc6ed8b1bde6f7741dbea18500a1049ea6"
+dependencies = [
+ "bytes",
+ "chrono",
+ "reqwest",
+ "serde",
+ "serde_json",
+ "sha1",
+ "thiserror",
+ "tokio",
+]
+
 [[package]]
 name = "encoding_rs"
 version = "0.8.28"
@@ -636,6 +654,12 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "path-clean"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ecba01bf2678719532c5e3059e0b5f0811273d94b397088b82e3bd0a78c78fdd"
+
 [[package]]
 name = "percent-encoding"
 version = "2.1.0"
@@ -972,8 +996,10 @@ version = "0.1.0"
 dependencies = [
  "bytes",
  "chrono",
+ "daedalus",
  "futures",
  "lazy_static",
+ "path-clean",
  "regex",
  "reqwest",
  "serde",
diff --git a/theseus/Cargo.toml b/theseus/Cargo.toml
index c4d8a9f57..a1750dcfe 100644
--- a/theseus/Cargo.toml
+++ b/theseus/Cargo.toml
@@ -9,6 +9,8 @@ edition = "2018"
 [dependencies]
 thiserror = "1.0"
 
+daedalus = "0.1.6"
+
 reqwest = { version = "0.11", features = ["json"] }
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
@@ -17,6 +19,7 @@ uuid = { version = "0.8", features = ["serde", "v4"] }
 bytes = "1"
 zip = "0.5"
 sha1 = { version = "0.6.0", features = ["std"]}
+path-clean = "0.1.0"
 
 regex = "1.5"
 lazy_static = "1.4"
diff --git a/theseus/src/launcher/args.rs b/theseus/src/launcher/args.rs
index a7e9b47d4..46dc99fc2 100644
--- a/theseus/src/launcher/args.rs
+++ b/theseus/src/launcher/args.rs
@@ -1,7 +1,11 @@
 use crate::launcher::auth::provider::Credentials;
-use crate::launcher::meta::{Argument, ArgumentValue, Library, Os, VersionType};
 use crate::launcher::rules::parse_rules;
 use crate::launcher::LauncherError;
+use daedalus::get_path_from_artifact;
+use daedalus::minecraft::{Argument, ArgumentValue, Library, Os, VersionType};
+use daedalus::modded::SidedDataEntry;
+use std::collections::HashMap;
+use std::io::{BufRead, BufReader};
 use std::path::Path;
 use uuid::Uuid;
 
@@ -13,63 +17,24 @@ pub fn get_class_paths(
     let mut class_paths = Vec::new();
 
     for library in libraries {
-        if library.downloads.artifact.is_some() {
-            if let Some(rules) = &library.rules {
-                if !super::rules::parse_rules(rules.as_slice()) {
-                    continue;
-                }
+        if let Some(rules) = &library.rules {
+            if !super::rules::parse_rules(rules.as_slice()) {
+                continue;
             }
-
-            let name_items = library.name.split(':').collect::<Vec<&str>>();
-
-            let package = name_items.get(0).ok_or_else(|| {
-                LauncherError::ParseError(format!(
-                    "Unable to find package for library {}",
-                    &library.name
-                ))
-            })?;
-            let name = name_items.get(1).ok_or_else(|| {
-                LauncherError::ParseError(format!(
-                    "Unable to find name for library {}",
-                    &library.name
-                ))
-            })?;
-            let version = name_items.get(2).ok_or_else(|| {
-                LauncherError::ParseError(format!(
-                    "Unable to find version for library {}",
-                    &library.name
-                ))
-            })?;
-
-            let mut path = libraries_path.to_path_buf();
-
-            for directory in package.split('.') {
-                path.push(directory);
-            }
-
-            path.push(name);
-            path.push(version);
-            path.push(format!("{}-{}.jar", name, version));
-
-            class_paths.push(
-                std::fs::canonicalize(&path)
-                    .map_err(|_| {
-                        LauncherError::InvalidInput(format!(
-                            "Library file at path {} does not exist",
-                            path.to_string_lossy()
-                        ))
-                    })?
-                    .to_string_lossy()
-                    .to_string(),
-            )
         }
+
+        if !library.include_in_classpath {
+            continue;
+        }
+
+        class_paths.push(get_lib_path(libraries_path, &library.name)?);
     }
 
     class_paths.push(
-        std::fs::canonicalize(&client_path)
+        crate::util::absolute_path(&client_path)
             .map_err(|_| {
                 LauncherError::InvalidInput(format!(
-                    "Specified client path {} does not exist",
+                    "Specified class path {} does not exist",
                     client_path.to_string_lossy()
                 ))
             })?
@@ -83,6 +48,45 @@ pub fn get_class_paths(
     }))
 }
 
+pub fn get_class_paths_jar<T: AsRef<str>>(
+    libraries_path: &Path,
+    libraries: &[T],
+) -> Result<String, LauncherError> {
+    let mut class_paths = Vec::new();
+
+    for library in libraries {
+        class_paths.push(get_lib_path(libraries_path, library)?)
+    }
+
+    Ok(class_paths.join(match super::download::get_os() {
+        Os::Osx | Os::Linux | Os::Unknown => ":",
+        Os::Windows => ";",
+    }))
+}
+
+pub fn get_lib_path<T: AsRef<str>>(libraries_path: &Path, lib: T) -> Result<String, LauncherError> {
+    let mut path = libraries_path.to_path_buf();
+
+    path.push(get_path_from_artifact(lib.as_ref())?);
+
+    let path = crate::util::absolute_path(&path).map_err(|_| {
+        LauncherError::InvalidInput(format!(
+            "Library file at path {} does not exist",
+            path.to_string_lossy()
+        ))
+    })?;
+
+    /*if !path.exists() {
+        if let Some(parent) = &path.parent() {
+            std::fs::create_dir_all(parent)?;
+        }
+
+        std::fs::File::create(&path)?;
+    }*/
+
+    Ok(path.to_string_lossy().to_string())
+}
+
 pub fn get_jvm_arguments(
     arguments: Option<&[Argument]>,
     natives_path: &Path,
@@ -97,7 +101,7 @@ pub fn get_jvm_arguments(
     } else {
         parsed_arguments.push(format!(
             "-Djava.library.path={}",
-            &*std::fs::canonicalize(natives_path)
+            &*crate::util::absolute_path(natives_path)
                 .map_err(|_| LauncherError::InvalidInput(format!(
                     "Specified natives path {} does not exist",
                     natives_path.to_string_lossy()
@@ -117,10 +121,12 @@ fn parse_jvm_argument(
     natives_path: &Path,
     class_paths: &str,
 ) -> Result<String, LauncherError> {
+    let mut argument = argument.to_string();
+    argument.retain(|c| !c.is_whitespace());
     Ok(argument
         .replace(
             "${natives_directory}",
-            &*std::fs::canonicalize(natives_path)
+            &*crate::util::absolute_path(natives_path)
                 .map_err(|_| {
                     LauncherError::InvalidInput(format!(
                         "Specified natives path {} does not exist",
@@ -208,7 +214,7 @@ fn parse_minecraft_argument(
         .replace("${assets_index_name}", asset_index_name)
         .replace(
             "${game_directory}",
-            &*std::fs::canonicalize(game_directory)
+            &*crate::util::absolute_path(game_directory)
                 .map_err(|_| {
                     LauncherError::InvalidInput(format!(
                         "Specified game directory {} does not exist",
@@ -220,7 +226,7 @@ fn parse_minecraft_argument(
         )
         .replace(
             "${assets_root}",
-            &*std::fs::canonicalize(assets_directory)
+            &*crate::util::absolute_path(assets_directory)
                 .map_err(|_| {
                     LauncherError::InvalidInput(format!(
                         "Specified assets directory {} does not exist",
@@ -232,7 +238,7 @@ fn parse_minecraft_argument(
         )
         .replace(
             "${game_assets}",
-            &*std::fs::canonicalize(assets_directory)
+            &*crate::util::absolute_path(assets_directory)
                 .map_err(|_| {
                     LauncherError::InvalidInput(format!(
                         "Specified assets directory {} does not exist",
@@ -281,3 +287,59 @@ where
 
     Ok(())
 }
+
+pub fn get_processor_arguments<T: AsRef<str>>(
+    libraries_path: &Path,
+    arguments: &[T],
+    data: &HashMap<String, SidedDataEntry>,
+) -> Result<Vec<String>, LauncherError> {
+    let mut new_arguments = Vec::new();
+
+    for argument in arguments {
+        let trimmed_arg = &argument.as_ref()[1..argument.as_ref().len() - 1];
+        if argument.as_ref().starts_with('{') {
+            if let Some(entry) = data.get(trimmed_arg) {
+                new_arguments.push(if entry.client.starts_with('[') {
+                    get_lib_path(libraries_path, &entry.client[1..entry.client.len() - 1])?
+                } else {
+                    entry.client.clone()
+                })
+            }
+        } else if argument.as_ref().starts_with('[') {
+            new_arguments.push(get_lib_path(libraries_path, trimmed_arg)?)
+        } else {
+            new_arguments.push(argument.as_ref().to_string())
+        }
+    }
+
+    Ok(new_arguments)
+}
+
+pub async fn get_processor_main_class(path: String) -> Result<Option<String>, LauncherError> {
+    Ok(tokio::task::spawn_blocking(move || {
+        let zipfile = std::fs::File::open(&path)?;
+        let mut archive = zip::ZipArchive::new(zipfile).map_err(|_| {
+            LauncherError::ProcessorError(format!("Cannot read processor at {}", path))
+        })?;
+
+        let file = archive.by_name("META-INF/MANIFEST.MF").map_err(|_| {
+            LauncherError::ProcessorError(format!("Cannot read processor manifest at {}", path))
+        })?;
+
+        let reader = BufReader::new(file);
+
+        for line in reader.lines() {
+            let mut line = line?;
+            line.retain(|c| !c.is_whitespace());
+
+            if line.starts_with("Main-Class:") {
+                if let Some(class) = line.split(':').nth(1) {
+                    return Ok(Some(class.to_string()));
+                }
+            }
+        }
+
+        Ok::<Option<String>, LauncherError>(None)
+    })
+    .await??)
+}
diff --git a/theseus/src/launcher/auth.rs b/theseus/src/launcher/auth.rs
index 0981010d6..909eb5d27 100644
--- a/theseus/src/launcher/auth.rs
+++ b/theseus/src/launcher/auth.rs
@@ -167,12 +167,39 @@ pub mod api {
 }
 
 pub mod provider {
+    use crate::launcher::auth::api::login;
+    use crate::launcher::LauncherError;
     use uuid::Uuid;
 
     #[derive(Debug)]
+    /// The credentials of a user
     pub struct Credentials {
+        /// The user UUID the credentials belong to
         pub id: Uuid,
+        /// The username of the user
         pub username: String,
+        /// The access token associated with the credentials
         pub access_token: String,
     }
+
+    impl Credentials {
+        /// Gets a credentials instance from a user's login
+        pub async fn from_login(username: &str, password: &str) -> Result<Self, LauncherError> {
+            let login =
+                login(username, password, true)
+                    .await
+                    .map_err(|err| LauncherError::FetchError {
+                        inner: err,
+                        item: "authentication credentials".to_string(),
+                    })?;
+
+            let profile = login.selected_profile.unwrap();
+
+            Ok(Credentials {
+                id: profile.id,
+                username: profile.name,
+                access_token: login.access_token,
+            })
+        }
+    }
 }
diff --git a/theseus/src/launcher/download.rs b/theseus/src/launcher/download.rs
index b26007a45..e50de820a 100644
--- a/theseus/src/launcher/download.rs
+++ b/theseus/src/launcher/download.rs
@@ -1,30 +1,36 @@
-use crate::launcher::meta::{
+use crate::launcher::LauncherError;
+use daedalus::get_path_from_artifact;
+use daedalus::minecraft::{
     fetch_assets_index, fetch_version_info, Asset, AssetsIndex, DownloadType, Library, Os, Version,
     VersionInfo,
 };
-use crate::launcher::LauncherError;
+use daedalus::modded::{fetch_partial_version, merge_partial_version, LoaderVersion};
 use futures::future;
 use std::fs::File;
-use std::io::{BufReader, Write};
+use std::io::Write;
 use std::path::Path;
 
 pub async fn download_version_info(
     client_path: &Path,
     version: &Version,
+    loader_version: Option<&LoaderVersion>,
 ) -> Result<VersionInfo, LauncherError> {
-    let path = &*client_path
-        .join(&version.id)
-        .join(format!("{}.json", &version.id));
+    let id = loader_version.map(|x| &x.id).unwrap_or(&version.id);
+
+    let path = &*client_path.join(id).join(format!("{}.json", id));
 
     if path.exists() {
         Ok(serde_json::from_str(&std::fs::read_to_string(path)?)?)
     } else {
-        let info = fetch_version_info(version)
-            .await
-            .map_err(|err| LauncherError::FetchError {
-                inner: err,
-                item: "version info".to_string(),
-            })?;
+        let mut info = fetch_version_info(version).await?;
+
+        if let Some(loader_version) = loader_version {
+            let partial = fetch_partial_version(&*loader_version.url).await?;
+
+            info = merge_partial_version(partial, info);
+
+            info.id = loader_version.id.clone();
+        }
 
         save_file(path, &bytes::Bytes::from(serde_json::to_string(&info)?))?;
 
@@ -50,7 +56,7 @@ pub async fn download_client(
         .join(&version_info.id)
         .join(format!("{}.jar", &version_info.id));
 
-    save_and_download_file(path, &client_download.url, &client_download.sha1).await?;
+    save_and_download_file(path, &client_download.url, Some(&client_download.sha1)).await?;
 
     Ok(())
 }
@@ -66,12 +72,7 @@ pub async fn download_assets_index(
     if path.exists() {
         Ok(serde_json::from_str(&std::fs::read_to_string(path)?)?)
     } else {
-        let index = fetch_assets_index(version)
-            .await
-            .map_err(|err| LauncherError::FetchError {
-                inner: err,
-                item: "assets index".to_string(),
-            })?;
+        let index = fetch_assets_index(version).await?;
 
         save_file(path, &bytes::Bytes::from(serde_json::to_string(&index)?))?;
 
@@ -113,7 +114,7 @@ async fn download_asset(
             "https://resources.download.minecraft.net/{}/{}",
             sub_hash, asset.hash
         ),
-        &*asset.hash,
+        Some(&*asset.hash),
     )
     .await?;
 
@@ -154,34 +155,9 @@ async fn download_library(
         }
     }
 
-    let name_items = library.name.split(':').collect::<Vec<&str>>();
-
-    let package = name_items.get(0).ok_or_else(|| {
-        LauncherError::ParseError(format!(
-            "Unable to find package for library {}",
-            &library.name
-        ))
-    })?;
-    let name = name_items.get(1).ok_or_else(|| {
-        LauncherError::ParseError(format!("Unable to find name for library {}", &library.name))
-    })?;
-    let version = name_items.get(2).ok_or_else(|| {
-        LauncherError::ParseError(format!(
-            "Unable to find version for library {}",
-            &library.name
-        ))
-    })?;
-
     let (a, b) = future::join(
-        download_library_jar(libraries_path, library, package, name, version),
-        download_native(
-            libraries_path,
-            natives_path,
-            library,
-            package,
-            name,
-            version,
-        ),
+        download_library_jar(libraries_path, library),
+        download_native(natives_path, library),
     )
     .await;
 
@@ -194,61 +170,51 @@ async fn download_library(
 async fn download_library_jar(
     libraries_path: &Path,
     library: &Library,
-    package: &str,
-    name: &str,
-    version: &str,
 ) -> Result<(), LauncherError> {
-    if let Some(library) = &library.downloads.artifact {
-        let mut path = libraries_path.to_path_buf();
+    let mut path = libraries_path.to_path_buf();
+    path.push(get_path_from_artifact(&*library.name)?);
 
-        for directory in package.split('.') {
-            path.push(directory);
+    if let Some(downloads) = &library.downloads {
+        if let Some(library) = &downloads.artifact {
+            save_and_download_file(&*path, &library.url, Some(&library.sha1)).await?;
         }
-
-        path.push(name);
-        path.push(version);
-        path.push(format!("{}-{}.jar", name, version));
-
-        save_and_download_file(&*path, &library.url, &library.sha1).await?;
+    } else {
+        save_and_download_file(
+            &*path,
+            &format!(
+                "{}{}",
+                library
+                    .url
+                    .as_deref()
+                    .unwrap_or("https://libraries.minecraft.net/"),
+                get_path_from_artifact(&*library.name)?
+            ),
+            None,
+        )
+        .await?;
     }
 
     Ok(())
 }
 
-async fn download_native(
-    libraries_path: &Path,
-    natives_path: &Path,
-    library: &Library,
-    package: &str,
-    name: &str,
-    version: &str,
-) -> Result<(), LauncherError> {
+async fn download_native(natives_path: &Path, library: &Library) -> Result<(), LauncherError> {
     if let Some(natives) = &library.natives {
         if let Some(os_key) = natives.get(&get_os()) {
-            if let Some(classifiers) = &library.downloads.classifiers {
-                #[cfg(target_pointer_width = "64")]
-                let parsed_key = os_key.replace("${arch}", "64");
-                #[cfg(target_pointer_width = "32")]
-                let parsed_key = os_key.replace("${arch}", "32");
+            if let Some(downloads) = &library.downloads {
+                if let Some(classifiers) = &downloads.classifiers {
+                    #[cfg(target_pointer_width = "64")]
+                    let parsed_key = os_key.replace("${arch}", "64");
+                    #[cfg(target_pointer_width = "32")]
+                    let parsed_key = os_key.replace("${arch}", "32");
 
-                if let Some(native) = classifiers.get(&*parsed_key) {
-                    let mut path = libraries_path.to_path_buf();
+                    if let Some(native) = classifiers.get(&*parsed_key) {
+                        let file = download_file(&native.url, Some(&native.sha1)).await?;
 
-                    for directory in package.split('.') {
-                        path.push(directory);
+                        let reader = std::io::Cursor::new(&*file);
+
+                        let mut archive = zip::ZipArchive::new(reader).unwrap();
+                        archive.extract(natives_path).unwrap();
                     }
-
-                    path.push(name);
-                    path.push(version);
-                    path.push(format!("{}-{}-{}.jar", name, version, parsed_key));
-
-                    save_and_download_file(&*path, &native.url, &native.sha1).await?;
-
-                    let file = File::open(&path).unwrap();
-                    let reader = BufReader::new(file);
-
-                    let mut archive = zip::ZipArchive::new(reader).unwrap();
-                    archive.extract(natives_path).unwrap();
                 }
             }
         }
@@ -260,14 +226,14 @@ async fn download_native(
 async fn save_and_download_file(
     path: &Path,
     url: &str,
-    sha1: &str,
+    sha1: Option<&str>,
 ) -> Result<bytes::Bytes, LauncherError> {
     let read = std::fs::read(path).ok().map(bytes::Bytes::from);
 
     if let Some(bytes) = read {
         Ok(bytes)
     } else {
-        let file = download_file(url, Some(sha1)).await?;
+        let file = download_file(url, sha1).await?;
 
         save_file(path, &file)?;
 
@@ -286,7 +252,16 @@ fn save_file(path: &Path, bytes: &bytes::Bytes) -> Result<(), std::io::Error> {
     Ok(())
 }
 
-async fn download_file(url: &str, sha1: Option<&str>) -> Result<bytes::Bytes, LauncherError> {
+pub fn get_os() -> Os {
+    match std::env::consts::OS {
+        "windows" => Os::Windows,
+        "macos" => Os::Osx,
+        "linux" => Os::Linux,
+        _ => Os::Unknown,
+    }
+}
+
+pub async fn download_file(url: &str, sha1: Option<&str>) -> Result<bytes::Bytes, LauncherError> {
     let client = reqwest::Client::builder()
         .tcp_keepalive(Some(std::time::Duration::from_secs(10)))
         .build()
@@ -295,7 +270,7 @@ async fn download_file(url: &str, sha1: Option<&str>) -> Result<bytes::Bytes, La
             item: url.to_string(),
         })?;
 
-    for attempt in 1..4 {
+    for attempt in 1..=4 {
         let result = client.get(url).send().await;
 
         match result {
@@ -340,17 +315,9 @@ async fn download_file(url: &str, sha1: Option<&str>) -> Result<bytes::Bytes, La
     unreachable!()
 }
 
-async fn get_hash(bytes: bytes::Bytes) -> Result<String, LauncherError> {
+/// Computes a checksum of the input bytes
+pub async fn get_hash(bytes: bytes::Bytes) -> Result<String, LauncherError> {
     let hash = tokio::task::spawn_blocking(|| sha1::Sha1::from(bytes).hexdigest()).await?;
 
     Ok(hash)
 }
-
-pub fn get_os() -> Os {
-    match std::env::consts::OS {
-        "windows" => Os::Windows,
-        "macos" => Os::Osx,
-        "linux" => Os::Linux,
-        _ => Os::Unknown,
-    }
-}
diff --git a/theseus/src/launcher/meta.rs b/theseus/src/launcher/meta.rs
deleted file mode 100644
index ac964b400..000000000
--- a/theseus/src/launcher/meta.rs
+++ /dev/null
@@ -1,205 +0,0 @@
-use chrono::{DateTime, Utc};
-use serde::{Deserialize, Serialize};
-use std::collections::HashMap;
-
-#[derive(Serialize, Deserialize, Debug)]
-#[serde(rename_all = "snake_case")]
-pub enum VersionType {
-    Release,
-    Snapshot,
-    OldAlpha,
-    OldBeta,
-}
-
-impl VersionType {
-    pub fn as_str(&self) -> &'static str {
-        match self {
-            VersionType::Release => "release",
-            VersionType::Snapshot => "snapshot",
-            VersionType::OldAlpha => "old_alpha",
-            VersionType::OldBeta => "old_beta",
-        }
-    }
-}
-
-#[derive(Deserialize, Debug)]
-#[serde(rename_all = "camelCase")]
-pub struct Version {
-    pub id: String,
-    #[serde(rename = "type")]
-    pub type_: VersionType,
-    pub url: String,
-    pub time: DateTime<Utc>,
-    pub release_time: DateTime<Utc>,
-}
-
-#[derive(Deserialize, Debug)]
-pub struct LatestVersion {
-    pub release: String,
-    pub snapshot: String,
-}
-
-#[derive(Deserialize, Debug)]
-pub struct VersionManifest {
-    pub latest: LatestVersion,
-    pub versions: Vec<Version>,
-}
-
-pub async fn fetch_version_manifest() -> Result<VersionManifest, reqwest::Error> {
-    reqwest::get("https://launchermeta.mojang.com/mc/game/version_manifest.json")
-        .await?
-        .json()
-        .await
-}
-
-#[derive(Serialize, Deserialize, Debug)]
-#[serde(rename_all = "camelCase")]
-pub struct AssetIndex {
-    pub id: String,
-    pub sha1: String,
-    pub size: u32,
-    pub total_size: u32,
-    pub url: String,
-}
-
-#[derive(Serialize, Deserialize, Debug, Eq, PartialEq, Hash)]
-#[serde(rename_all = "snake_case")]
-pub enum DownloadType {
-    Client,
-    ClientMappings,
-    Server,
-    ServerMappings,
-    WindowsServer,
-}
-
-#[derive(Serialize, Deserialize, Debug)]
-pub struct Download {
-    pub sha1: String,
-    pub size: u32,
-    pub url: String,
-}
-
-#[derive(Serialize, Deserialize, Debug)]
-pub struct LibraryDownload {
-    pub path: String,
-    pub sha1: String,
-    pub size: u32,
-    pub url: String,
-}
-
-#[derive(Serialize, Deserialize, Debug)]
-pub struct LibraryDownloads {
-    pub artifact: Option<LibraryDownload>,
-    pub classifiers: Option<HashMap<String, LibraryDownload>>,
-}
-
-#[derive(Serialize, Deserialize, Debug)]
-#[serde(rename_all = "snake_case")]
-pub enum RuleAction {
-    Allow,
-    Disallow,
-}
-
-#[derive(Serialize, Deserialize, Debug, Eq, PartialEq, Hash)]
-#[serde(rename_all = "snake_case")]
-pub enum Os {
-    Osx,
-    Windows,
-    Linux,
-    Unknown,
-}
-
-#[derive(Serialize, Deserialize, Debug)]
-pub struct OsRule {
-    pub name: Option<Os>,
-    pub version: Option<String>,
-    pub arch: Option<String>,
-}
-
-#[derive(Serialize, Deserialize, Debug)]
-pub struct FeatureRule {
-    pub is_demo_user: Option<bool>,
-    pub has_demo_resolution: Option<bool>,
-}
-
-#[derive(Serialize, Deserialize, Debug)]
-pub struct Rule {
-    pub action: RuleAction,
-    pub os: Option<OsRule>,
-    pub features: Option<FeatureRule>,
-}
-
-#[derive(Serialize, Deserialize, Debug)]
-pub struct LibraryExtract {
-    pub exclude: Option<Vec<String>>,
-}
-
-#[derive(Serialize, Deserialize, Debug)]
-pub struct Library {
-    pub downloads: LibraryDownloads,
-    pub extract: Option<LibraryExtract>,
-    pub name: String,
-    pub natives: Option<HashMap<Os, String>>,
-    pub rules: Option<Vec<Rule>>,
-}
-
-#[derive(Serialize, Deserialize, Debug)]
-#[serde(untagged)]
-pub enum ArgumentValue {
-    Single(String),
-    Many(Vec<String>),
-}
-
-#[derive(Serialize, Deserialize, Debug)]
-#[serde(untagged)]
-pub enum Argument {
-    Normal(String),
-    Ruled {
-        rules: Vec<Rule>,
-        value: ArgumentValue,
-    },
-}
-
-#[derive(Serialize, Deserialize, Debug, Eq, PartialEq, Hash)]
-#[serde(rename_all = "snake_case")]
-pub enum ArgumentType {
-    Game,
-    Jvm,
-}
-
-#[derive(Serialize, Deserialize, Debug)]
-#[serde(rename_all = "camelCase")]
-pub struct VersionInfo {
-    pub arguments: Option<HashMap<ArgumentType, Vec<Argument>>>,
-    pub asset_index: AssetIndex,
-    pub assets: String,
-    pub downloads: HashMap<DownloadType, Download>,
-    pub id: String,
-    pub libraries: Vec<Library>,
-    pub main_class: String,
-    pub minecraft_arguments: Option<String>,
-    pub minimum_launcher_version: u32,
-    pub release_time: DateTime<Utc>,
-    pub time: DateTime<Utc>,
-    #[serde(rename = "type")]
-    pub type_: VersionType,
-}
-
-pub async fn fetch_version_info(version: &Version) -> Result<VersionInfo, reqwest::Error> {
-    reqwest::get(&version.url).await?.json().await
-}
-
-#[derive(Serialize, Deserialize, Debug)]
-pub struct Asset {
-    pub hash: String,
-    pub size: u32,
-}
-
-#[derive(Serialize, Deserialize, Debug)]
-pub struct AssetsIndex {
-    pub objects: HashMap<String, Asset>,
-}
-
-pub async fn fetch_assets_index(version: &VersionInfo) -> Result<AssetsIndex, reqwest::Error> {
-    reqwest::get(&version.asset_index.url).await?.json().await
-}
diff --git a/theseus/src/launcher/mod.rs b/theseus/src/launcher/mod.rs
index 2b7994eae..8bf104060 100644
--- a/theseus/src/launcher/mod.rs
+++ b/theseus/src/launcher/mod.rs
@@ -1,14 +1,15 @@
-use crate::launcher::auth::provider::Credentials;
+use daedalus::minecraft::{ArgumentType, VersionInfo};
 use std::path::Path;
 use std::process::{Command, Stdio};
 use thiserror::Error;
 
-pub mod args;
-pub mod auth;
-pub mod download;
-pub mod java;
-pub mod meta;
-pub mod rules;
+pub use crate::launcher::auth::provider::Credentials;
+
+mod args;
+mod auth;
+mod download;
+mod java;
+mod rules;
 
 #[derive(Error, Debug)]
 pub enum LauncherError {
@@ -18,11 +19,13 @@ pub enum LauncherError {
         url: String,
         tries: u32,
     },
+    #[error("Failed to run processor: {0}")]
+    ProcessorError(String),
     #[error("Invalid input: {0}")]
     InvalidInput(String),
     #[error("Error while managing asynchronous tasks")]
     TaskError(#[from] tokio::task::JoinError),
-    #[error("Error while reading/writing to the disk")]
+    #[error("Error while reading/writing to the disk: {0}")]
     IoError(#[from] std::io::Error),
     #[error("Error while spawning child process {process}")]
     ProcessError {
@@ -35,57 +38,237 @@ pub enum LauncherError {
     FetchError { inner: reqwest::Error, item: String },
     #[error("{0}")]
     ParseError(String),
+    #[error("Error while fetching metadata: {0}")]
+    DaedalusError(#[from] daedalus::Error),
+}
+
+const META_URL: &str = "https://staging-cdn.modrinth.com/gamedata";
+
+pub async fn fetch_metadata() -> Result<
+    (
+        daedalus::minecraft::VersionManifest,
+        daedalus::modded::Manifest,
+        daedalus::modded::Manifest,
+    ),
+    LauncherError,
+> {
+    let (game, forge, fabric) = futures::future::join3(
+        daedalus::minecraft::fetch_version_manifest(Some(&*format!(
+            "{}/minecraft/v0/manifest.json",
+            META_URL
+        ))),
+        daedalus::modded::fetch_manifest(&*format!("{}/forge/v0/manifest.json", META_URL)),
+        daedalus::modded::fetch_manifest(&*format!("{}/fabric/v0/manifest.json", META_URL)),
+    )
+    .await;
+
+    Ok((game?, forge?, fabric?))
+}
+
+#[derive(Debug, Eq, PartialEq, Clone, Copy)]
+pub enum ModLoader {
+    Vanilla,
+    Forge,
+    Fabric,
+}
+
+impl Default for ModLoader {
+    fn default() -> Self {
+        ModLoader::Vanilla
+    }
 }
 
 pub async fn launch_minecraft(
     version_name: &str,
+    mod_loader: Option<ModLoader>,
     root_dir: &Path,
     credentials: &Credentials,
 ) -> Result<(), LauncherError> {
-    let manifest = meta::fetch_version_manifest().await.unwrap();
+    let (game, forge, fabric) = fetch_metadata().await?;
 
-    let version = download::download_version_info(
-        &*root_dir.join("versions"),
-        manifest
-            .versions
+    let versions_path = crate::util::absolute_path(root_dir.join("versions"))?;
+    let libraries_path = crate::util::absolute_path(root_dir.join("libraries"))?;
+    let assets_path = crate::util::absolute_path(root_dir.join("assets"))?;
+    let legacy_assets_path = crate::util::absolute_path(root_dir.join("resources"))?;
+
+    let mut version = download::download_version_info(
+        &versions_path,
+        game.versions
             .iter()
             .find(|x| x.id == version_name)
             .ok_or_else(|| {
                 LauncherError::InvalidInput(format!("Version {} does not exist", version_name))
             })?,
+        match mod_loader.unwrap_or_default() {
+            ModLoader::Vanilla => None,
+            ModLoader::Forge | ModLoader::Fabric => {
+                let loaders = if mod_loader.unwrap_or_default() == ModLoader::Forge {
+                    &forge
+                        .game_versions
+                        .iter()
+                        .find(|x| x.id == version_name)
+                        .ok_or_else(|| {
+                            LauncherError::InvalidInput(format!(
+                                "Version {} for mod loader Forge does not exist",
+                                version_name
+                            ))
+                        })?
+                        .loaders
+                } else {
+                    &fabric
+                        .game_versions
+                        .iter()
+                        .find(|x| x.id == version_name)
+                        .ok_or_else(|| {
+                            LauncherError::InvalidInput(format!(
+                                "Version {} for mod loader Fabric does not exist",
+                                version_name
+                            ))
+                        })?
+                        .loaders
+                };
+
+                let loader = if let Some(version) =
+                    loaders.get(&daedalus::modded::LoaderType::Stable)
+                {
+                    Some(version.clone())
+                } else if let Some(version) = loaders.get(&daedalus::modded::LoaderType::Latest) {
+                    Some(version.clone())
+                } else {
+                    None
+                };
+
+                Some(loader.ok_or_else(|| {
+                    LauncherError::InvalidInput(format!(
+                        "No mod loader version found for version {}",
+                        version_name
+                    ))
+                })?)
+            }
+        }
+        .as_ref(),
     )
     .await?;
 
-    download_minecraft(&version, root_dir).await?;
+    let client_path = crate::util::absolute_path(
+        root_dir
+            .join("versions")
+            .join(&version.id)
+            .join(format!("{}.jar", &version.id)),
+    )?;
+    let natives_path = crate::util::absolute_path(root_dir.join("natives").join(&version.id))?;
 
-    let arguments = version.arguments.unwrap();
+    download_minecraft(
+        &version,
+        &versions_path,
+        &assets_path,
+        &legacy_assets_path,
+        &libraries_path,
+        &natives_path,
+    )
+    .await?;
+
+    if let Some(processors) = &version.processors {
+        if let Some(ref mut data) = version.data {
+            data.insert(
+                "SIDE".to_string(),
+                daedalus::modded::SidedDataEntry {
+                    client: "client".to_string(),
+                    server: "".to_string(),
+                },
+            );
+            data.insert(
+                "MINECRAFT_JAR".to_string(),
+                daedalus::modded::SidedDataEntry {
+                    client: client_path.to_string_lossy().to_string(),
+                    server: "".to_string(),
+                },
+            );
+            data.insert(
+                "MINECRAFT_VERSION".to_string(),
+                daedalus::modded::SidedDataEntry {
+                    client: version_name.to_string(),
+                    server: "".to_string(),
+                },
+            );
+            data.insert(
+                "ROOT".to_string(),
+                daedalus::modded::SidedDataEntry {
+                    client: root_dir.to_string_lossy().to_string(),
+                    server: "".to_string(),
+                },
+            );
+            data.insert(
+                "LIBRARY_DIR".to_string(),
+                daedalus::modded::SidedDataEntry {
+                    client: libraries_path.to_string_lossy().to_string(),
+                    server: "".to_string(),
+                },
+            );
+
+            for processor in processors {
+                if let Some(sides) = &processor.sides {
+                    if !sides.contains(&"client".to_string()) {
+                        continue;
+                    }
+                }
+
+                let mut cp = processor.classpath.clone();
+                cp.push(processor.jar.clone());
+
+                let child = Command::new("java")
+                    .arg("-cp")
+                    .arg(args::get_class_paths_jar(&libraries_path, &cp)?)
+                    .arg(
+                        args::get_processor_main_class(args::get_lib_path(
+                            &libraries_path,
+                            &processor.jar,
+                        )?)
+                        .await?
+                        .ok_or_else(|| {
+                            LauncherError::ProcessorError(format!(
+                                "Could not find processor main class for {}",
+                                processor.jar
+                            ))
+                        })?,
+                    )
+                    .args(args::get_processor_arguments(
+                        &libraries_path,
+                        &processor.args,
+                        data,
+                    )?)
+                    .output()
+                    .map_err(|err| LauncherError::ProcessError {
+                        inner: err,
+                        process: "java".to_string(),
+                    })?;
+
+                if !child.status.success() {
+                    return Err(LauncherError::ProcessorError(
+                        String::from_utf8_lossy(&*child.stderr).to_string(),
+                    ));
+                }
+            }
+        }
+    }
+
+    let arguments = version.arguments.unwrap_or_default();
 
     let mut child = Command::new("java")
         .args(args::get_jvm_arguments(
-            arguments
-                .get(&meta::ArgumentType::Jvm)
-                .map(|x| x.as_slice()),
-            &*root_dir.join("natives").join(&version.id),
-            &*args::get_class_paths(
-                &*root_dir.join("libraries"),
-                version.libraries.as_slice(),
-                &*root_dir
-                    .join("versions")
-                    .join(&version.id)
-                    .join(format!("{}.jar", &version.id)),
-            )?,
+            arguments.get(&ArgumentType::Jvm).map(|x| x.as_slice()),
+            &natives_path,
+            &*args::get_class_paths(&libraries_path, version.libraries.as_slice(), &client_path)?,
         )?)
         .arg(version.main_class)
         .args(args::get_minecraft_arguments(
-            arguments
-                .get(&meta::ArgumentType::Game)
-                .map(|x| x.as_slice()),
+            arguments.get(&ArgumentType::Game).map(|x| x.as_slice()),
             version.minecraft_arguments.as_deref(),
             credentials,
             &*version.id,
             &version.asset_index.id,
             root_dir,
-            &*root_dir.join("assets"),
+            &assets_path,
             &version.type_,
         )?)
         .current_dir(root_dir)
@@ -106,29 +289,27 @@ pub async fn launch_minecraft(
 }
 
 pub async fn download_minecraft(
-    version: &meta::VersionInfo,
-    root_dir: &Path,
+    version: &VersionInfo,
+    versions_dir: &Path,
+    assets_dir: &Path,
+    legacy_assets_dir: &Path,
+    libraries_dir: &Path,
+    natives_dir: &Path,
 ) -> Result<(), LauncherError> {
-    let assets_index = download::download_assets_index(&*root_dir.join("assets"), &version).await?;
-
-    let legacy_dir = root_dir.join("resources");
+    let assets_index = download::download_assets_index(assets_dir, version).await?;
 
     let (a, b, c) = futures::future::join3(
-        download::download_client(&*root_dir.join("versions"), &version),
+        download::download_client(versions_dir, version),
         download::download_assets(
-            &*root_dir.join("assets"),
+            assets_dir,
             if version.assets == "legacy" {
-                Some(legacy_dir.as_path())
+                Some(legacy_assets_dir)
             } else {
                 None
             },
             &assets_index,
         ),
-        download::download_libraries(
-            &*root_dir.join("libraries"),
-            &*root_dir.join("natives").join(&version.id),
-            version.libraries.as_slice(),
-        ),
+        download::download_libraries(libraries_dir, natives_dir, version.libraries.as_slice()),
     )
     .await;
 
diff --git a/theseus/src/launcher/rules.rs b/theseus/src/launcher/rules.rs
index 1970c8852..43c40b814 100644
--- a/theseus/src/launcher/rules.rs
+++ b/theseus/src/launcher/rules.rs
@@ -1,5 +1,5 @@
 use crate::launcher::download::get_os;
-use crate::launcher::meta::{OsRule, Rule, RuleAction};
+use daedalus::minecraft::{OsRule, Rule, RuleAction};
 use regex::Regex;
 
 pub fn parse_rules(rules: &[Rule]) -> bool {
@@ -9,10 +9,8 @@ pub fn parse_rules(rules: &[Rule]) -> bool {
 pub fn parse_rule(rule: &Rule) -> bool {
     let result = if let Some(os) = &rule.os {
         parse_os_rule(os)
-    } else if rule.features.is_some() {
-        false
     } else {
-        true
+        rule.features.is_none()
     };
 
     match rule.action {
diff --git a/theseus/src/lib.rs b/theseus/src/lib.rs
index da52d023b..dbf0e2036 100644
--- a/theseus/src/lib.rs
+++ b/theseus/src/lib.rs
@@ -6,3 +6,4 @@
 #![warn(missing_docs, unused_import_braces, missing_debug_implementations)]
 
 pub mod launcher;
+mod util;
diff --git a/theseus/src/util.rs b/theseus/src/util.rs
new file mode 100644
index 000000000..48d4fdc5a
--- /dev/null
+++ b/theseus/src/util.rs
@@ -0,0 +1,17 @@
+use std::path::{Path, PathBuf};
+use std::{env, io};
+
+use path_clean::PathClean;
+
+pub fn absolute_path(path: impl AsRef<Path>) -> io::Result<PathBuf> {
+    let path = path.as_ref();
+
+    let absolute_path = if path.is_absolute() {
+        path.to_path_buf()
+    } else {
+        env::current_dir()?.join(path)
+    }
+    .clean();
+
+    Ok(absolute_path)
+}