wanted to add something else i've realized: i just took down the big lv 23 xuanwu at lv 15 in what was a significantly more stressful fight than hydra ever was. i'd encourage you to take advantage of the fact that there's no longer a level cap by grinding as little as possible - the game actually works even when enemies are more than 3 levels ahead of you now!

i haven't gotten to the next boss, but i will say that i've found myself only fighting regular demons (outside of doing quests) for the purpose of negotiating. i feel like thus far this game's been balanced around assuming you just wanna get straight to the point, which i'm cool with

having just beat hydra last night on hard, i think your criticisms are more a product of you understanding the way the game's designed above anything else. that much is clear from the fact that you knew to use dampeners, which is definitely v's biggest learning curve imo

personally i was a good 3 levels under that fight and yoko didn't serve much use to me there at all. heavy lifting was courtesy of chad warden, mermaid, azumi, daemon and neko shogun. didn't really seem worthwhile to have another party member using items when it'd have just meant fewer turn presses being used effectively

her having tarunda doesn't mean a whole lot to me either there seeing that i fought hydra before she unlocked it - but even so, lots of my demons already had access to it. neko shogun's got fang breaker, c-wizzy's had tarunda for a while - hell, i don't think yoko even had it by the time i did that fight. and i've been doing all the sidequests too. essences aren't hard to come by and i don't think those aogami ones are all that great either