Twice a game, he can make a mafia kill resemble another kill, such as Juggernaut, Serial Killer, Potion Master, Coven Leader, Arsonist etc.
It's not overpowered as:
1) Another unique will realize there's a fake, just as two Juggernaut kills on the same night
2) The faction will know it's fake (Coven seeing a Coven attack that didn't exist)
3) Like Forger, Spy will see two roles visiting. If a consort or blackmailer is involved, then three roles
4) There would be no Mafia kill seen that turn
It will resonate with:
1) Forger, obviously
2) Consort - if the Mafia knows, say, someone is a Potion Master, the consort can roleblock the Potion Master and make them attack elsewhere
3) Blackmailer - see above