Tarsiel

Tarsiel is a Fallen Angel and a member of the Order of the Blackened Denarius. He first appears in Small Favor.

Small Favor
In Small Favor, Polonius Lartessa orders him to find and take out Jared Kincaid, during plot to take the Archive at the Shedd Aquarium. It either drowned or was killed by either Anastasia Luccio, Michael Carpenter, or Sanya at the aquarium.

It was one of the eleven coins stolen by Thorned Namshiel at Demonreach and presumably given to Tessa.