Terai

is a member of the disbanded faction of Konohagakure's ANBU: Root.

Background
As a member of Root, Terai was likely trained to lose emotions in order to better accomplish missions. As Root members each uses a codename, it is unknown what Terai's real name is, if he even has one. Even though the organisation has been officially disbanded, Terai remains loyal to its head, Danzō Shimura.

Five Kage Summit Arc
Before leaving to attend the Kage Summit, Danzō instructed him to find Kabuto Yakushi before Anko Mitarashi, who was doing the same at that point in time.

Terai