For dark, I used Satan team. I don't know what some people are using in Satan team, but this was scary.
For Nightmare, I used maxed PR Diablo with my under skilled sprites all ame 4 though and Morris ally
For water, I used Yuki. Seriously long grind for the team, overheal stage is killer with 5 weathered multiple times. Boss 1st life is no big deal, use actives or don't. I used Florice to remove the attack debuff. Make sure to bring some heart converters. 2 Yuki isn't quite enough. I brought Dagon as well and still had some scares, but my Yuki is only skill 12 (waiting to evolve water slime to max her skill)