Tera

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

Background
Tera, like most members of the group was likely adopted into the organisation as a young orphan to better lose his emotions. As the Root members each uses a codename, it is unknown what Tera's real name is, if Tera even has one. Even though the organisation has been officially disbanded, Tera remains loyal to its head, Danzō.

Five Kage Summit Arc
Tera and Dajimu had both been secretly assigned by Danzō to assassinate Anko Mitarashi, but due to the village's situation at that time, their mission was postponed in preference of finding Kabuto Yakushi before she did.

Trivia

 * Tera has so far only been mentioned once by name, and has yet to make an actual appearance.