Board Thread:Boruto Discussions/@comment-25319479-20181020083112/@comment-35480222-20181020211924

Elveonora wrote: Well....
 * Can use Rasengan
 * Can summon Toads
 * By all means a former Konoha Shinobi, considering his chakra is registered

How is he not Jiraiya then? well I don't remember excactly why but pretty much there where 4 reasons: age and body don't match, KK uses genjustu, KK is too much methodical, and Jiraya ghost has been shown.