There's no side effect If you're already buddy buddy with them. Like demonstrate by killer bee.
And no other jinchuriki truly make this thing vague.
Yeah, that's my main problem
I mean just look at Luffy from One Piece, all of his gears have some kind of side effect that it's bad for him
The kyuubi mode wouldn't look so OP if there was some kind of side effect for Naruto like the constant use of it would essentially ruin Naruto's mind and his own personality and he would end up kind of "fused " with the fox, not his own person anymore
Of course the kyuubi would also lose his own mind and personality , so it would be a bad thing for both
Edited by Nar123, 04 June 2015 - 02:16 AM.