In order to get a foothold in the criminal underworld, Grendel introduced himself to Ciccone by killing Ciccone's chief assassin and enforcer, and offering Ciccone himself as a replacement. Ciccone agreed to employ Grendel. Grendel served as the chief enforcer for the Ciccone family before he made his move to take over control of the family (which itself was just a stepping stone to taking over all of America's organized crime).
Theodore Ciccone presents himself as a Catholic. As is common with Mafioso, he was raised in an Italian Catholic family. But Theodore Ciccone's Catholicism appears to be merely part of a publicly respectable facade. He does not appear have any genuine commitment to Catholic teachings.
In the scene below, Theodore Ciccone is donating $56,000 from his front company to a Catholic charity for the purpose of supporting Catholic religious missions and Catholic orphanages. He donates the money through Father Anuncio, a Catholic priest who has known Theodore Ciccone since childhood. Despite this generous and welcome donation, Theodore Ciccone displays his lack of true commitment to his religion by telling the priest a vulgar and racist joke while they are sitting next to each other. Ciccone is then drawn away from this charity event by one of his Mafia hirelings. He leaves immediately to go meet with the assassin he had commissioned to kill some people.
From: "Devil's Assumption", written by Matt Wagner, with art and lettering by Andy Kuhn; reprinted in Grendel: Red, White & Black; Dark Horse Books: Milwaukie, Oregon (2005); pages 29-30: