Not a very skilled assassin
Edwin was a tiefling who lived on Hell Street in Sigurdsholm with his childhood friend, Edith. Edwin grew resentful of humans for their unjust treatment of his race, and tapped into his infernal heritage to get revenge, becoming a warlock.
Edwin was a member of Steel-Eyed Susan‘s gang until Susan was captured and executed. Edwin made a deal with Fulkhard to revive Susan, and claimed her revival was a sign of Arawn’s favor, creating the Black Masks from the former gang members and converts from the slums of Sigurdsholm. Edwin urged them to rise up and kill members of the City Guard, which they did. He also caught Forman trying to leave the cult, and ordered Halde to curse him.
When Amalie left the Black Masks, Edwin used his infernal powers to burn down her apartment. He then led the Black Masks to their secret meeting-place in the Seidhrskjold Wizards’ College library to ambush the party. The party killed Susan and routed the Black Masks, and Edwin teleported away.
Edwin bought a vial of assassin’s blood from Hygelac, and crept into Halde’s apartment to assassinate her. However, the party was also sleeping there, and killed Edwin. Amalie and Taavi then smuggled his body into the Necromancy Department.
Image source: Wizards of the Coast.