make sure there are only 9 people with bijuu .
lol it would be cool to start out like a kid and slowly grow up, like if you were born with a bijuu placed inside of you. the way i feel it should be first come first serve for the bio
and rinnegan has to be earned, i hope its strategy involved, because i hate easy , and simple games that anyone can conquer.
the more you can level up stats : weapons, health chakra , speed, intelligence, etc
that will make the game better , and like each clan should have a special power over another , like for example
nara clan , have extra intelligence and what ever else etc. lol
basically the more complex the game, the more users bro. good luck lol