|“||Now you'll never know what I want.||„|
| — Sinnerman to Lucifer after blinding himself|
in "The Sinnerman"
The Sinnerman is a criminal mastermind who previously operated in the Midwest. Marcus Pierce claims that he encountered him in Chicago. Pierce says that he ran away to Los Angeles after the Sinnerman killed his brother.
Lucifer Morningstar believes the Sinnerman was responsible for kidnapping him at the end of season 2. The Sinnerman knows that Lucifer is the devil and trapped him in a room closed off by reinforced steel to subdue his supernatural strength. He also knows about Lucifer's powers of learning about people's desires and after being captured by the police, he intentionally blinded himself so Lucifer's powers would not work on him.
In "All About Her", after being exposed as Cain, Pierce admits that the Sinnerman was his right-hand man and the closest thing he had to a friend. However, Pierce claims that the Sinnerman went rogue and that he does not know why the Sinnerman did what he did. Thus, Pierce concludes, "I had to take him out."
In "A Devil of My Word", Pierce eventually returns to his role as the real Sinnerman in an attempt to kill Lucifer and create a new life for himself, knowing that the latter would never stop hunting him down for the death of Charlotte. He draws Chloe and Lucifer into a planned ambush with several other men, temporarily rendering Lucifer vulnerable. This plan however, fails after Lucifer shields the incoming gun shots with his wings. Lucifer's invincibility returns after he flies Chloe away from the building, and he eventually kills Pierce with Mazikeen's blade in a final fight. This marked the official death of the Sinnerman.
The Sinnerman is a "slightly depraved" criminal mastermind. He is an intimidating figure whose existence scares numerous killers that previously worked for him. Sinnerman was one of the few people to know Lucifer was the Devil and come prepared. In their meeting, he was shown to be completely committed to fighting him, as he blinded himself without a second thought in order to avoid Lucifer's powers.
He is also quite psychotic as when Chloe Decker offered to take him in quietly, he declined as he claimed their fight was enjoyable. Sinnerman appeared to not value his own life as he attempted to sway Marcus Pierce into killing him.
- Marksman: Whilst his true capabilities have not yet been shown, he appears to be a skilled marksman when dueling with Chloe Decker.
- Expert tactician: Sinnerman is a clever tactician that he remains one step ahead of Lucifer's attempts to catch him. He kills two people that Lucifer did favors for to grab his attention and called him to intentionally lure Lucifer into an abandoned building and was clever enough to work out that Lucifer's strength cannot penetrate through reinforced steel.
- Pain resistance: The Sinnerman was able to gouge out his own eyes without a sound, showing only mild discomfort at the act. Even after Maze tortured him close to death, he was still able to stand up, move about, and even struggle with Lucifer.
|#1||"They're Back, Aren't They?"||Mentioned|
|#2||"The One with the Baby Carrot"||Mentioned|
|#10||"The Sin Bin"||Appears|
|#12||"All About Her"||Mentioned|
|#17||"Let Pinhead Sing!"||Mentioned|
- The song "Sinnerman" was sung by Lucifer in "Favorite Son" when his wings were stolen by Renny.
- Though not stated, the Sinnerman is Pierce's "fall guy", allowing police to think they caught him. This would allow Pierce to hide out a few decades and restart the Sinnerman identity with a new proxy.