So he's actually 13, but somehow aged 8 more years in like a week to increase his power, in addition to gaining a KG? I think someone's been watching a little bit too much HxH. I would like more information on how exactly that sudden aging and acquiring a KG happened. As far as I know, a KG can really only be gotten through birth or stealing it from another with that KG.

Edit: Also, if he's from the lands to the west of the Land of Earth and Wind, does that mean he didn't know what chakra was before coming to Iwagakure? His story seems to suggest that might be the case, which would match up with the naruto world's lore.