How much corrupted meat did you have in your inventory? Beelzebub does crazy damage if you have more than a handful.
You also don't need to absorb those 100mp curses. Better to not do it in fact, it's kind of a trap.
"Even on story mode, apparently the game has completely abandoned any pretense that pure is a legitimate option."
And yet lots of people manage pure on not just normal but higher difficulties.
"There's a reason nobody does your wiki for you. And the reason nobody on your team has done it is probably because none of you have any clue either."
The developer definitely has a clue, and has beaten every boss in the game without popping the collar on pure. More strategy tips on the wiki would be nice though, I agree on that.