During the war he went on missions with the Diablerie. He was also the leader.
Return of the Diablerie
Gallow rejoins The Diablerie with all of the former members (except China Sorrows and Baron Vengeous). He was presumed by many to be the Diablerie's leader, until it was revealed to be Batu. He tried to recruit China back into the Diablerie, but she refuses. He then tries to kill her, but she escapes through a secret trap door. He, Gruesome Krav and Murder Rose also attacked Tanith Low after Emmett Peregrine's death. Gallow later kidnaps Guild and is seen at Liffey Bridge during the exchange of victims.
At Aranmore Farm, he is forced to cut his arm off using a Cleaver's scythe so that he isn't possessed by a Faceless One. He was tricked into thinking that the symbol on his arm was a barrier against the Faceless Ones by Batu, but it was in fact a fake. Gallow disappears after the fight and is not mentioned again.
Rise of the Death Bringer
Gallow appears again in Death Bringer. He has a new arm but it is covered by a glove. He becomes allies again with China Sorrows so that they can bring down the Church of the Faceless. China accepts his request. She tells him to find a list of twelve names that will help recover the Church of the Faceless so they can assassinate them, along with Eliza Scorn.
Gallow manages to retrieve the twelve names, and at the Requiem Ball he arranges to meet with China outside Gordon's house, where the ball is being held. But when China gets to him, she finds Gallow dead in his car- with the top of his head on his lap. He was presumably killed by Eliza as on the dashboard there was a note reading "Too late, sweetie".
Magic and Abilties
Gallow is an Adept however his Adept ability is unknown as he has never utilised it in a fight before but he easily dispatched Remus Crux with his bare hands.