This is in my opinion the best water main lineup in the game. This lineup lineup has helped me win against ppl that are a lot stronger than me and i hope it can help you guys too.The ninjas that are included are Chojuro, Mei and Ao.
The formation looks like this:
Main Chojuro x
Mei Ao x
x x x
Talents: 3,2,1,1,1 and summon is Gamaken. (Gamachu could work but then Meis chase isn't included)
I hope this lineup helps you.