@StayTofik Because that avatar is not tied to Kurama but the Otsutsuki clan bloodline. Kurama just provides the chakra like how the people back then provided Ashura the chakra to use the avatar state.
@lastborn_1j No that skin you see under the makeup belongs to a body he took over. His original body is like the make up. If you bother watching the flashback with him you'd know this.
@Megadetta "Non canon" Once again canon doesn't exist in Japanese media. It is either "Original Works" or "Fan Works". All official Dragon Ball media fall under "original works".