Activate Ashnod's Altar by sacrificing Twisted Sewer-Witch, adding CC.
When Twisted Sewer-Witch dies, Nim Deathmantle triggers, causing you to pay 4 to return Twisted Sewer-Witch from your graveyard to the battlefield, and attach Nim Deathmantle to it.
When Twisted Sewer-Witch enters the battlefield, it triggers, creating a 1/1 Rat creature token, and then creating a Wicked Role Aura token attached to each Rat you control.
Activate Ashnod's Altar by sacrificing the Rat, adding CC.
The Wicked Role token triggers, causing each opponent to lose 1 life.
Repeat.
This clever loop transforms Twisted Sewer-Witch into an endless engine of sacrifice and resurrection by letting Ashnod's Altar turn creatures into the exact mana needed to fuel Nim Deathmantle's revival trigger. Each iteration restarts the whole process while generating disposable Rat tokens and draining your opponents dry through the bitter demise of their accompanying Wicked Role tokens.