First of all, thanks for trying it with that! It's good to know it works >vv< I'm glad you had fun!
Yasei squints in his idle animation which I know can look a little weird if you don't catch onto it >vv<; There are PP restoring berries you can sometimes buy at Ms. Lagombi, though they're pretty expensive- I recommend conserving your PP by using Standard Attacks when you can, that way you can have lots of PP for when you need it! I think if you ask Yasei for the Guidance called "Making Attacks" it goes over that, in case you need help there :3
Also I recommend using Tactics so you can tell Yasei to run away, or give him an herberry, etc, it helps a lot! Thank you again ^vv^