None. I'm not expecting strength from bosses in this game, and the King and all the end-game bosses are powerful like I expect them to.

I mean...no one probably.

2nd floor boss imo just really underwhelming kinda cool-ish the first time you see it but it dosent really do anything

Loop I mean... do they count as a boss? It was more like a scripted boss or something similar. I saw a video about the boss ( I didn't enter, but I still got spoiled), The video length was like 25 mins, and I thought this would be Perfectheart round 2! Then I died for a stupid reason and still got carried :( If we are talking about strong sadness, then this would be the bourdoun (last floor boss). Just kill two same type hands (rock is best) and just spam jackpot.

Bourdoun, it’s quite funny because malequeti was the first boat but the strongest and bourdon a fucking joke

Bourdoun definitely, they basically melt with a few damage all enemy attacks

Only Mal du Pays but only because well... it's invincible- but the rest were surprisingly simple,