Devil by the Deed
In Devil by the Deed, the Grendel storyline presented as a back-up story in Mage, Nuncio was a low-level criminal. He was used by Grendel (Hunter Rose) to pass along information to the police, stating that there would be a hit on a movie mogul, Anson Reynolds. Normally very businesslike, this time he was paranoid and nervous.
His tip led Grendel's arch-foe Argent into a trap, embarrassing him. However, it also led to a emotional gulf between Hunter Rose and his adopted ward, Stacy Palumbo. Grendel eventually killed Nuncio and carved a large "G" into his chest.
In Devil Eyes, a two-issue arc in the main Grendel series, Captain Wiggins, a foe of Grendel, wrote a novel about Nuncio. The broad strokes of the original story about Nuncio, and Wiggins' novel about him, are the same, but it is implied that Wiggins may have fabricated the new extra details in his book.
In Wiggins' book, Nuncio is an unattractive but confident rat. He goes out in the nightlife of the city and picks up on information, which he sells to others. He is a lowlife, but is not a major criminal.
One night, while in a bathroom, he hears some people talking about Grendel: he is going to kill Anson Reynolds, a movie mogul. Grendel hasn't killed anyone in years, so this is big news. Nuncio doesn't believe it at first, and isn't sure whether to say anything about it anyway, but finally goes to police headquarters to tell them what he knows. He goes through a lengthy interview with Argent and other police.
They stake out Reynolds' house, but it was all a trick: Grendel set it all up so Argent ends up falling several stories in front of a crowd, embarrassing himself. Nuncio, reading the headlines, realizes he was set up, and gets paranoid: Grendel will probably come to take care of him soon!
Nuncio barricades himself in his apartment and slowly becomes paranoid and eventually totally nuts. At first, he takes somewhat reasonably precautions: fortifying the door, turning off the lights, being careful about getting food. Nuncio, who has always spent every night out on the town, begins to go stir-crazy. He watches TV endlessly.
He turns the fire escape into a trap. He steams open his mail, then replaces it, so it looks like he's not looking at it. He takes drugs to stay awake and to go to sleep. He stops using the sink, toilet, and shower, convinced that Grendel may send a bomb through the plumbing. He uses the bathtub for his waste, and it begins to smell horribly, but his fear is great enough for him to ignore it. This goes on for weeks.
Meanwhile, Grendel has totally forgotten about him. He is only concerned that his plan backfired, and his adopted daughter Stacy is now depressed over Argent's humiliation. He begins to think about ways to take his mind off this problem.
The situation becomes worse for Tommy. The landlord and the health inspector keep knocking on the door because of the smell. Finally Tommy can't take it any more. He spazzes out on the barricaded door with a crowbar. He feels better, and decides to chance it and go out. He east at a restaurant, but gets worried on the way back. He thinks he's being followed.
He runs in and hears a noise on the fire escape. He sets off the trap, then looks out: Grendel is hanging on, safe! Tommy runs, but Grendel pursues him effortlessly. He finally runs him to ground and kills him in a parking lot, carving a bloody "G" in his chest.