Does prevail and undress work together(if u equip both skills, do they stack)?
Also, as an individual skill, which works better, undress or prevail?


Also about Eushully weapons, how do u unlock them? I only have the most basic Eushully weapons. The Iron ones. And about some ultimate weapons, how do u unlock them?

yes they stack, prevail is better because it's guaranteed to work always once low on hp (plus it comes with a bracelet)

to unlock the eu weapons you got to do the eu quests and level up the weapons you unlock first

to unlock utlimate weapons you got to recruit all the non clone-only people and you'll become meister, then you'll get a quest to get 500 kills with wil and you'll become magnus and unlock ultimate stuff

Prevail gives bonus in both offenses and both defenses when on low HP, lower HP = higher bonus.
Undress 1/2/3 gives a fixed +2/4/6 to all stats (maybe not speed), and +10/20/30 to accuracy, evasion, and critical rate once your HP goes below 50%.

Regarding "which is better" question: Prevail gives much better stat boosts and starts working earlier (Prevail III has +20% at <80% HP and +50% at <50% HP), but Undress also gives +30 Hit/Evd and +15 Crit (at lvl III); AFAIK, such Evd bonus can be a life-saver sometimes.
And yes, you can use both at once, and gain both bonuses.

For each angelmaid, recipes for second and third weapons are unlocked by leveling the previous weapon. Next recipe requires you to complete their personal quests (which are given when they reach lvl55). Some more recipes are unlocked after reaching Meister/Magnus ranks, and clearing EX-dungeons.

Ultimate weapons require Magnus rank, which is gained by being Meister and having 500 kills on Wil. By the way, if you start a new playthrough after that, you'll have to get 500 kills again to get the recipes back.