I think now kaguya? It's Kimimaro or other character of sound clan but i don't get it could it be that Kimimaro or five sound ninja is one of the relationship rikodou?
The Kaguya clan is Kimimaro's clan...the one that went extinct when they tried to attack the Bloody Mist.
However, the princess's name was Ootsutsuki Kaguya, and her son's name was Ootsutsuki Bagoromo. This means that their clan/family name was not Kaguya, but rather it was Ootsutsuki. Therefore, Kimimaro is not related to the So6P...his clan's name just happened to be the same as the princess's first name.