Dajimu

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

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

Five Kage Summit Arc
Dajimu and Tera 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

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