Kaguya Clan

The is a now extinct clan, known for their savage battle tactics and archaic values, and descendents of Kaguya Ōtsutsuki, as selected few have inherited a derivative of her original ability to manipulate one's bone structures.

Background
The Kaguya clan were descendants of Kaguya Ōtsutsuki, and selective few, namely Kimimaro, possessed the kekkei genkai Shikotsumyaku from Kaguya's original bone-manipulating ability. This ability was so powerful that even the war-loving Kaguya clan feared it.

The clan was noted for being very savage and battle-hungry, having no tactics when entering battle that they initiated simply to show off their ferocity. It was due to this failed attempt to prove themselves that the entire clan was killed off when attacking Kirigakure; even when surrounded and completely outmatched, they refused to back down, preferring to fight to the death simply to entertain their own bloodlust to the last.

Kimimaro was the only one of the clan to survive, as he did not share the same urge for barbaric slaughter as the others, and after being adopted by Orochimaru, he would live as the last of the Kaguya clan for several years, but eventually died of a terminal illness.

Abilities
The Kaguya clan was noted for being very savage, relying on raw brute force and no battle tactics, which led the near entirety of them being wiped out when facing the highly organised military forces such as that of Kirigakure. Because of this, they are fearless (if not insane or delusional), recklessly entering the battlefield and refusing to retreat even when defeat is clear, simply for the thrill of slaughter.

Shikotsumyaku
As descendents of Kaguya Ōtsutsuki, a select few were able to inherit the Shikotsumyaku Kekkei Genkai, a derivative of their ancestor's All-Killing Ash Bones Kekkei Mōra, which allowed them to manipulate their skeletal structure to weaponise bones for battle. This ability was so powerful, regarded as the ultimate taijutsu ability, that the other members of the clan feared it.

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.

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.