Dungeons and other structures now have bosses spawning in them, more than 29 boss variants of vanilla entities

These bosses have custom abilities, stats, loot and behaviour/AI so each one is a different challenge.
Requires Cuboard dependency to be installed in newer versions

All bosses are created through datapacks, by default the mod already includes 29 Bosses.

They're fully customizable and you can add new bosses yourself easily. You can make a boss of about any entity, including other mod's entities.

Check here to see the full guide on creating a custom boss: https://gist.github.com/someaddons/aa5986b9495863c3b55947a07e243395

Commands for testing bosses:

/brutalbosses spawnboss all spawns all bosses
/brutalbosses spawnboss random spawns a random boss
/brutalbosses spawnboss <filename> spawns a specific boss

This mod is compatible with any structure which adds lootable chests/containers, due to bosses spawning next to those chests.
Structures which are using vanilla loottables are inherently compatible, others may be added explicitly through datapacks.
Includes compatibility for the following structure mods by default:

Awesome Dungeon
Awesome Dungeon Edition Ocean

Awesome dungeon nether
Awesome dungeon end

Bygone Nether
Dungeon Crawl
Dungeons Enhanced
Dungeons Plus
End Remastered
Goblins & Dungeons
Illagers+
Infernal Expansion

It takes a pillage
Mo' Structures

Phillips ruins
Stoneholm, Underground Villages
The Graveyard

The Lost castle
Towns and Towers
Towers of the Wild: Reloaded
Towers of the Wild: Additions
Valhelsia Structures
When Dungeons Arise

William wythers
YUNG's Better Dungeons
YUNG's Better Strongholds

Missing a mod? you can easily add it with a datapack, check the spawning section of the boss creation guide: https://gist.github.com/someaddons/aa5986b9495863c3b55947a07e243395 List of all bosses:

Brutal Bosses - Custom Bosses