Abarth
Abarth is an Outsider mentioned once in Preamble. When an Annex vendor protests the inflexibility of a couple of Marcus’ goons who are shaking him down for protection money, one of the goons says, “… or you can wait for Abarth to show up. See if the curs take city vouchers.”
Though we don’t know anything about him or the specifics of his relationship to Marcus at this point, avoiding a visit from Abarth is clearly an incentive to find a way to pay the local slumlord.
At the end of Interlocation, the Hangman’s Horde is razing Ricky’s slum. When he is discovered, Ricky asks to negotiate with Abarth, suspecting this is his gang coming to collect - or deliver punishment for - a late payment to Marcus. Hank corrects Ricky’s confusion but shows gratitude to Ricky for confirming the names of Abarth and Marcus.
We see Abarth for the first time at the Ruckus. He tells Hank some of the members of the Horde were kicked out of the gathering for unspecified aggression. Abarth also insinuates that the Horde has gone hungry at times, and gives an open invitation for them to join his tribe. When Hank tells him they will not bow down for “a slumlord’s scarps,” Abarth says some bowing might do him and his mountain cult some good.
Later, Abarth talks to Joan when she arrives. Joan was formerly general of Abarth’s tribe, and is against warfare between the tribes. According to Tim, she says it wouldn’t be worth the losses. She may be the reason Hank’s typical “king of the outlands” challenges of fights to the death have not been accepted by Abarth - they seem to be on relatively good terms, though he chides her for her belief in “a voice in the Demon’s head.”