Party Slog is his a persona he takes on that is VERY destructive and has the ability to destroy worlds. Party Slog usually comes out when Slog is extremely bored and wants to party. The other disgustoids do not like Party Slog and will try to prevent him from coming out as much as possible.
Festro, Gweelok, Dingle, and Fart are all his best bros and roommates. However, in Mother-Zombie's fanfiction Getting Out Alive: Chapter 3, Festro began to accuse Slog of plotting to kill everyone. Though it was untrue, Festro stuck with his theory which hurt Slog's feelings alot. Despite the event, Slog still doesn't have any ill-will toward Festro and his accusations.
Ramona Desdemona- They had a tiny mini date at one point, going into the date thinking they would be perfect for each other and coming out of the date realizing how dead wrong they were. Ramona thinks he's a complete and utter moron and wants nothing to do with him. Slog wishes Ramona didn't disregard him as much as she does. So far, they've had no real interaction in Mother-zombie's fanfiction Getting Out Alive.
Billy Baggins- Right from the start of Mother-zombie's fanfiction Getting Out Alive, they've had some sort of friendship going on. They are constantly seen hanging out with each other. Billy has a very high level of patience with Slog, unlike others. Billy also constantly defends Slog, especially in Getting Out Alive: Chapter 4 when Festro began to accuse Slog of being a traitor.