Board Thread:Versus Debates/@comment-30355627-20170226234835/@comment-30168130-20170305021227

he got a seal. simple. and a seal made kurama's chakra his own, even if he didn't have kurama inside him. that's why he has the whisker marks by the way, and by being inside his mom, while she was a jinchuriki, which transmitted kurama's chakra to him, over time. the same probably happened to his sp chakra, as well, cuz of the seal.