Ultris: Boss Expansion
by limesplatus
Players who want new encounters across a world can use Ultris: Boss Expansion, a set of eight bosses with their own structures, items and quests.
What it does
Each of the eight bosses has a dedicated arena, unique attack patterns, its own music and sounds, and quests with rewards. Some appear early in a playthrough and others are aimed at late-game players, and every boss is tied to new structures and special items that are scattered through the world for exploration.
The mod ships as a Fabric, Forge and Quilt build, and a Data pack version is also available for servers that prefer not to install a loader mod. Ultris requires a server install and is published for 1.19 – 1.20.1 across seven release versions. The author notes that the project is older and no longer maintained, and recommends the optional resource pack when the data pack is used.
Ultris is released under a custom license and is not open source. Two other catalog mods build on it: Boss Checklist - Ultris Compatibility and Ultris Bug Fixes.
Key features
Eight bosses
The mod adds eight bosses with separate arenas, attack sets and fight stages.
Boss structures and items
New structures generate in the world, and they hold special items that tie into the boss encounters.
Quests and rewards
Each boss comes with its own quest chain and reward list, so fights connect to progression.
Boss music and sounds
Every boss has its own soundtrack and sound effects, including tracks credited to outside musicians.
Admin summon menu
Bosses can be summoned through a function-based admin menu, which is useful for testing fights.
Gallery
Compatibility
Latest build for each game version and loader.
Only full game releases are shown. This mod publishes no snapshot builds.
Required by 2 mods
Use cases
Early-game encounters
Some bosses appear early, so a new world gains challenges before the late game.
End-game challenges
The stronger bosses suit players who have already gathered gear and want harder fights.
Who it’s for: Players who enjoy boss fights and exploration in survival worlds, and server owners who want custom encounters with quests and rewards.
How it compares
Cataclysm Summons is open source under the MIT License and runs on Forge and NeoForge for 1.19.2 – 1.20.1, with client and server both needing it. Bossominium is a Forge mod for 1.19.4 – 1.20.1 under All rights reserved, also requiring both sides. Ultris is server-required with an optional client, and its custom license is not open source.
| Mod | Loaders | Game versions | Environment | Updated |
|---|---|---|---|---|
| Ultris: Boss Expansion | Fabric, Forge and Quilt | 1.19 – 1.20.1 | Server required, client optional | 2023-11-19 |
| Cataclysm Summons | Forge and NeoForge | 1.19.2 – 1.20.1 | Client and server | 2025-05-14 |
| Bossominium | Forge | 1.19.4 – 1.20.1 | Client and server | 2025-01-26 |
Questions
Does a player need Ultris installed to join a server running it?
Is there a version without a mod loader?
How are the bosses summoned for testing?
In the catalog
Ultris: Boss Expansion is one of 7,216 Magic mods on ModsFinder, and one of 3,630 Magic mods for Fabric. 34,764 mods support Minecraft 1.20.1.
More from limesplatus
Similar mods
What the author says
note: older and currently unmaintained project! If using the Datapack version, I recommend installing the >> Optional Resourcepack <<
Official listing
- Modrinth page
- modrinth.com/mod/ultris
- Owner
- limesplatus
- Published
- 2022-11-24
- Updated on Modrinth
- 2023-11-19
- Facts verified
- 2026-10-15