Grigori

Grigori (保護者 (グリゴリ), Gurigori; Japanese for "Guardian") are with  powers. Within Quincy lore, they were obscurely known as the "Fallen Quincy" (落伍滅却師, Rakugo Kuinshī); heritics who turned their backs on the pride of the Quincy and sided with the treacherous Shinigami in exchange for power.

Behind the Scenes
The name, Grigori, originates from the Books of Enoch which describe the fall of the angels known as Watchers. It is said that they fell from heaven after succumbing to their lust for humans. This is intended to tie directly into the origin of how the Grigori first came about in this rendition within the Bleach universe.