Adding my voice to the chorus that Bleaty shouldn't be a random boss. He does enough damage to one-shot even a level ten character. There is a very narrow range of strategies that can deal with that, and not all dungeon spawns (prehaps not even most) give you the tools to implement them.
Desktop Dungeons is basically a puzzle game. Challenging puzzles are fine, but this is like handing someone a jigsaw puzzle without all the pieces.