i need ideas but...for the ghosts you need to defeat them to get them,so if you wanted amidamaru you would have to defeat him first!!!
amidamaru
bason
lee bailong
koropokkuru
togakero
racoon
fox
eliza
mosuke
morphea
jaguar
pascal avaf
spirit of fire
great spirit
note:if a friend on here dies instead of becoming a shinigami he could be your spirit ally but he can only if he was level 100 when he died