Board Thread:Naruto Discussions/@comment-44437908-20200710093820/@comment-32685487-20200713035352

https://naruto.fandom.com/wiki/Shikotsumyaku

" It very rarely manifests within members of the Kaguya clan, of which Kimimaro was the last survivor. "

If you go back and check you will see it is very rare and only Kimimaro had the KKG as far as we know. In fact the rest of the clan had him caged up and some were even scared of him because of it. Like Hashirama he was the only known member of his clan to actually have the KKG, while at the same time they never said that they were the only ones period. Both are rare KKG's.