Zadkiel is an Archangel with the favour of God. Though at first he fought alongside the other angels in the war against Hell, he tired of the death, loss and sorrow, and chose to settle instead in the Cathedral of Umbar, which stands at the heart of a town lost in time that needs guardianship more than any other place In Between.
The people of Umbar know Zadkiel resides in the cathedral, but he doesn't usually appear before them unless directly petitioned to. To most, he is simply a rumour, or a vision—a being whom they take for granted exists.
Here in Umbar, the divine and diabolical powers often mix and mingle with bizarre results, the same way new diseases brew and emerge where sewage collects. Many of the ensuing troubles eventually involve him, when the victims come seeking help or protection.
One of the several he's become familiar with of late is Amari, a magician who first stumbled upon the cathedral when they sent a child there to protect her from the death come to claim her. Ever since, they have struck up a deal with Zadkiel to bring all the lost children they find.