Billy and his twin Ben lived in Gainesville, Georgia with their mother Donna and father Allen. When the zombie outbreak began, Allen and Donna had heard that Atlanta would be the safest place to be due to the military's attempt to make it a safe zone. Thankfully, they came later and found that was not the case. After their car breaks down, the family finds Glenn, Dale, Amy, and Andrea, who had set up camp on the south side.
Written by Robert Kirkman and drawn by Tony Moore.
Major Story Arcs
Once hooked up with the survivors outside Atlanta, Ben and Billy become friends with Sophia and Carl, the other kids in the group. The four of them are often watched together. The two don't factor too much into the early days.
Upon finding a gated community, the twins share a room with their parents. The next day the adults go out to investigate the other houses and the twins are left behind. The group ends up needing to retreat after Donna gets eaten. Allen tells the boys as the RV drives away and the twins find comfort in Lori's arms.
With a grieving father, the twins are mainly watched by others. The group joins up with Hershel's farm and Andrea makes a concerted effort to get Allen to care for Ben and Billy. The effort fails and the group is eventually kicked off the farm.
The boys continue to be watched by others, but Allen begins to snap out of his grief. He vows to help his boys more by helping the group. His first foray into cleaning the prison ends up with him getting bit. Ben and Billy can't help but watch another parent slip away from them. Allen does eventually die and his last wish is that Dale and Andrea take care of the boys. They do. Ben and Billy continue to play with Carl and Sophia but get taken away when Woodbury becomes a threat. Dale and Andrea take the boys (along with Glenn and Maggie) back to Hershel's farm while Woodbury destroys the safety of the prison.
Despite not appearing in the live action show on AMC, Billy's role is depicted by Kyla Kenedy, who plays Mika Samuels. Mika is a girl left in the care of Rick's group with her sister Lizzy, much like Billy and his twin were left with Dale and Andrea in the books. Mika is killed by her sister in a similar manner as Billy. It is presumed that Carol kills Mika's brain so that her corpse doesn't turn.