Rei had like 5x the chakra of a kage after he bonded with tsunade and he was getting 5x more chakra each bond and his body strengthened so shouldn't he be super op one shot kaguya level after he has bonded with 3 more people or is this the author just conveniently forgetting about that?
Actually out of all villages, kumo was the best, it had good guys leading it, just didn't had some three eyed old man's sons in it, or they would have been leading the world