When you are playing with a partner get you statis up to Great(you can tell when it's Great because it will say Great under you health) and use a spirit power attack and both you and your partner will attack.Look at the instuvtion book for deitails on how to get your statis to up to Great.You will need to look in the back of the book.

To get human Inuyasha you have to beat Shippo's story.