Allready mentioned you can't be jinchuriki and player at same time, jinchuriki will be world or instance bosses. they drops scrolls, pets etc. BTW: pets system is not summoning pet jutsu, it's two dif things. Pet will be near you 24/7 you can disband him or call him he gives you extra stats like - stamina, chakra etc and he got level to but he can't attack. You need him feed every 12 hours or he just will be unhappy and run away. You can edit as you own pet stats what you need for your character. Level system will be lower 2 levels when yours are it will be balanced and safe and helps in combat or instances plus i think pet should give extra skills like self heal teleport to home village, 3second shield when you change map from being a victim of rogue ninja, mini bag to carry some of your stuff. jinchuriki pets will be most of the rariest in game they should be dropable from raid bosses and drop chance 0.5% plus you can't sell them to auction house it's be rariest and unique to.