The Archangel Schueler, also called the Holy Schueler, was one of the archangels, the identities assumed by the Operation Ark administrative council.

Schueler defined the punishment to be visited upon those who violated the proscriptions of Langhorne and Jwo-jeng, as described in the Book of Schueler. In time, his order became the single most powerful order of the Church of God Awaiting, controlling the Office of the Inquisition.

Schueler Strait was also named after him. (OAR)

It was believed that he bestowed the Stone of Schueler and the Key upon the Wylsynn Family, which are his descendants (HFAF)

Schueler taught that for the good of their souls, and for the possibility of reclaiming them even at the very last moment from Shan-wei and the Pit, the Inquisition dares not relent lest the transitory illusion of mercy in this world lead to their utter damnation in the next. (HFAF)

The content of the Vision and the fact that his book wasn't one of the original books of the Writ makes Merlin Athrawes unsure about the real author of his book (and thus the real opinion of Schueler about mercy) (HFAF)