Billy (Comic Series)

"What's a 'Segs'?"

- Billy to his parents, Allen and Donna.

Billy was Allen and Donna's twin son and the brother of Ben. He was unofficially adopted by Dale and Andrea after his parents' death.

Post-Apocalypse
He doesn't seem to understand what is happening in the world as it is. After his mother, Donna, died, he didn't seem to understand what had happened, although he was very sad. When the survivors settled down at The Prison, Billy lost his father to a lurker attack. He's later adopted by Dale and Andrea.

When Rick, Glenn, and Michonne arrive back from Woodbury, everybody understands that Woodbury are coming to attack The Prison. Dale decides to leave with a few others, including Billy. Billy leaves The Prison along with Ben, Dale, Andrea, Sophia, Glenn, and Maggie. Opposite of his brother, he didn't seem to have mental illnesses.

Killed By

 * Ben

On the road to Washington D.C., Billy is brutally knifed to death by Ben, who's convinced that Billy will come back. The group debates killing Ben to protect themselves, but takes no immediate action. In the night, Carl Grimes sneaks into the van where Ben is locked up, and executes him. The twins are buried side by side.

Allen
The twins loved their father. They were very sad when their last parent died.

Donna
The twins loved their mother, but when Donna died, they weren't able to understand what was happening.

Ben
Billy and Ben weren't just twins, they were also playmates. They usually did everything together.

Andrea
Ben, at least, loved Andrea, like his own mother. Not much is seen about Billy's and Andrea's relationship, but it can be inferred that he liked her.

Dale
Billy, along with Ben, was usually seen playing with Dale. In the back of a truck on the road to D.C., either Ben or Billy was sleeping with their head on Dale's lap.

Trivia

 * Robert Kirkman answered the question whether naming characters the same name: Billy, Eugene, Chris, Eric, Jim, and Bruce was an oversight, "It's not oversight at all. It's completely unrealistic for a group of people to meet at random and never encounter the same names."
 * Billy and Ben were the first twins in the Comic Series, the second pair being Rachel and Susie Greene.
 * Allen, Donna, and Ben appear in the third season of the TV Series, without Billy.
 * It is said in the Walking Dead script book that Ben and Billy are 4 years old.