Kaguya Clan

The is a now extinct clan, known to have been very barbaric. Select few, namely Kimimaro, possessed the kekkei genkai Shikotsumyaku; this ability was so powerful that even the warmongering Kaguya clan feared it. With the exception of Kimimaro, the clan was killed off when attacking Kirigakure in a failed attempt to show off their ferocity. The clan was very savage and had no tactics when going to battle, and refused to back down even when surrounded and completely outmatched, preferring to fight to the death for fun. Kimimaro would for years live as the last member of the Kaguya clan, but eventually died of a terminal disease.

Apparently, the members who possess the Shikotsumyaku abilities have a different bodily structure, as when Kimimaro was fatally ill, Kabuto Yakushi claimed there had been too little information on his body to give any medical treatment.