BLOODLINK

Hell was never meant to be cleared alone.

BLOODLINK is an experimental multiplayer co-op mod for ULTRAKILL. Bring your friends into the campaign through LAN/direct IP or Unity Relay join codes.

Watch the showcase

Features

• Co-op rooms for up to four players.
• LAN discovery, direct IP connections and Unity Relay join codes.
• Synchronized players, enemies, combat, breakable objects and level progression.
• Shared checkpoints, respawning, spectator mode and recovery during encounters.
• V1 color customization, presets and an interactive model preview.
• Optional friendly fire controlled by the host.
• Teammate HUD with names, health bars and death status.

Version: 0.112.0 / network protocol: 56. Every player must use this same version.

Install with a mod manager

1. Install BLOODLINK in an ULTRAKILL profile using Thunderstore Mod Manager or r2modman.
2. Allow the manager to install the BepInEx dependency.
3. Launch the game using the manager's modded launch option.
4. Select MULTIPLAYER in the main menu or press F7.

The package includes the mod's runtime libraries and a minimal BepInEx configuration enabling HideManagerGameObject = true, which is required by this mod's scene lifecycle. If you keep an existing BepInEx configuration, ensure that this option is enabled under [Chainloader] in your active profile's BepInEx/config/BepInEx.cfg.

Play together

Unity Relay

The host selects HOST WITH UNITY RELAY, then shares the join code. Other players enter it in RELAY JOIN CODE and select JOIN RELAY ROOM. Relay needs an internet connection and the configured Unity services to be available.

Direct IP or LAN

The host creates a room. Other players enter the host address and matching UDP port, or use FIND LAN ROOMS on the same network. The default port is 27015. Direct connections across the internet require a reachable host address and network configuration.

In the level

Press READY when the requested level has finished loading. Use F7 to open the multiplayer menu. The host can toggle FOGO AMIGO in HOST SETTINGS. Customization is available in the V1 appearance tab.

Experimental release

Synchronization, encounter recovery and spectator behavior are still being refined. Some bosses, scripted sequences, doors or custom levels may behave differently in multiplayer. The included build passed local protocol/transport checks; those checks do not verify all gameplay or visual behavior inside Unity.

If you report a problem, include the mod version, level, host/client role, what happened and the relevant BepInEx/LogOutput.log from the affected profile.

Manual installation

Install BepInEx 5 x64 first, close the game, then copy the contents of this package's BepInEx/ folder into the game's BepInEx folder. This Thunderstore package depends on the BepInEx pack for the loader; it does not contain a second copy of winhttp.dll or doorstop_config.ini.

Included libraries

LiteNetLib and the Unity Transport, Authentication, QoS and Relay libraries are included alongside the plugin. See THIRD-PARTY-NOTICES.txt for the supplied dependency notices.

BLOODLINK is an unofficial community mod and is not affiliated with ULTRAKILL's developers.