For me the most annoying boss is Falz. It's ok that the game was made to play in TEAM, but there's few things as frustrating as an encounter where you play a class that just CAN'T... HELP.... DYING! I find it too abusive the arm swipe doing a fixed amount of damage regardless of DFP, it's like saying that regardless of whether you play like a champ or have strategies that get you through where chars 10 levels higher than you fall, in the end it's only raw might and uber stats that count... yeah right, encourage the use of CodeBreaker, mat duping and so, way to go Sonic Team.<p>What's worse, things like that just ban low-hp classes completely of quests like Towards the Future, where the only way to get SS rank is both getting all monsters AND not dying once. A fonewearl wanting to get Giant Plantain Fan won't be able to do it until getting the 1380-something required hp to survive swipe, which would be somewhere around level 160-something unless she gets lucky with hp mats, point at which such a weapon becomes irrelevant anyway, so if you're a Fonewearl wanting such a weapon at a point where said weapon still makes any difference you need either a HU-something friend to get the weapon for you or getting a comfy chair for it will be a loooooooooooong wait.<p>I know there's always Challenge Mode if you want to get S-rank weapons, but still I don't like discrimination unless there's a good reason for that (or at least better than "you're not uber").<p>In the case of De'rol I have nothing against him, as he's merely a "buffer boss" to see whether you're prepared to get to ruins (if you beat De'rol you beat Vol Opt). Yes, he has those annoying unescapable hits, but at least they're not 1-hit kills (unless he scores a critical and you're really too low level) AND both your DFP and resistances count, which makes him a considerably better sport.<p>An annoying close second, however, would be the Sol Dragon from Episode 2, that part where he splits in 2 and you fight him on the ground while his other self bombards you with paralyzing electricity or ice is pure, frustratig hell.