- Origin: The Grim Adventures of Billy & Mandy
- Gender: Male
- Status: Alive
- Family: Harold (father), Gladys (mother)
Powerpuff Girls DoujinshiEdit
Billy had a few cameo apparences. The first time he was watching the fight along with the class between the Powerpuff Girls, Dexter and the Dread Dragon. Later he was seen along with Ed collecting cookies and make a huge mountain of it and slide down of it.
The Grim Tales From Down BelowEdit
Billy was mentioned a few times during the story of Grim Jr. He was always very weird and doing crazy things, Grim didn't knew when it was Billy's time since his hourglass was very weird with twist and thing like that. When it was Billy's time he was practically sinless because of his stupidity which granted him a place in Heaven, but because of his stupidity he got kicked out of Heaven and was placed in Hell instead, but his stupidity got him kicked out of there as well. Billy found his way home as a wandering spirit and went on a few adventures with Grim since Mandy wasn't Grim's friend anymore. Billy's fate was unknown after that.
Billy is the main protagonist. He is a young happy-go-lucky child with an extremely low IQ of -5. He was outperformed by a shovel on an IQ test. He has an extremely large, pink nose, wears a blue and white striped shirt, and covers his redheaded hair with a red hat. His main affiliations are Grim and Mandy. Mandy is Billy's best friend, though she treats him more like a servant than a friend. It has been hinted several times that Billy may have underlying feelings for Mandy that even he (in his stupidity) may not fully realize. Billy is definitely kinder to Grim than Mandy is, and while he may go against the Reaper's advice and use him as a plaything, he appears to genuinely like him. Of the two children, Billy is the one who most often tells Grim that he's his "best friend".