The Kaguya clan (かぐや一族, Kaguya Ichizoku) is a now extinct clan, known for their savage battle tactics and archaic values. Select few, namely Kimimaro, possessed the kekkei genkaiShikotsumyaku which was presumably inherited from Kaguya Ōtsutsuki.[1] This ability was so powerful that even the war-loving 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.[2]
Apparently, the members who possess the Shikotsumyaku abilities have a different body structure than others, as when Kimimaro was fatally ill, Kabuto Yakushi claimed there had been too little information on his body to give any medical treatment.[2]
Trivia
The clan shares their name with the earliest known user of its kekkei genkai: Kaguya. The marking on their foreheads also seem to be replications of her own shortly cut eyebrows which served as visible sign of her nobility.
In an interview with Naruto creator Masashi Kishimoto, he mentioned that the two markings on the Kaguya clan members' foreheads are based off of the marks on aristocrats during the Heian Period.