The Truenamed Angel is an Empyreal Knight who spends most of his time battling the legions of hell. His true name was among those listed in The Book of Many Names, and Magister Nendir Mithmiras researched his name to determine who and what he was, and latter summoned him for assistance.
On Lamashan 9th, 2 KE, an assassin and his harem attempted to kill many of the ruling council of Wayland by luring them into a cave, pouring oil and/or gunpowder into it, and collapsing the cave with potentially lethal amounts of smoke sealed inside. The council escaped the cave and later found that the assassin and his harem had led four diseased horses into Wayland, along with spreading a plague of nine different diseases around the city.
Facing a potentially apocalyptic plague, Magister Nendir summoned The Truenamed Angel by speaking his name so the council could ask him for help. The angel was reluctant to help at first, but when he understood it was not just one plague, but nine of them, and not due to a fault of the leadership of Wayland, the angel agreed to cure everyone. To do this, he required a body. The council turned to Artemis, but High Priest Arazmes volunteered instead.
Working through Arazmes, the angel removed all disease from everyone in Wayland. Arazmes was left temporarily blinded and severely weakened by the experience.
The angel told us that the Saints were not demigods, just powerful and malevolent outsiders. He had the same view of the Harbingers. He also told us that they were all causing harm in the world, as even the harbingers were granting great power to those who should not have it.
Before he left, he told us he did not want to be summoned again unless the forces of hell were literally pouring into the world somewhere.