Shawn Greene (TV Series)

Shawn Greene is Hershel's step-son, Maggie's step-brother, and Beth's half-brother. His zombified incarnation was kept in the Greene family barn along with several other zombies including his mother, Annette.

Greene Family Farm
Almost nothing is known about his life prior to the outbreak. Shawn likely moved onto the farm following Annette's marriage to Hershel. Shawn was just a newborn child when he moved to the Greene Family Farm. His biological father is likely to have been out of the picture, since Shawn has his step-father's last name.

Post-Apocalypse
Sometime after the initial outbreak, Shawn was killed by walkers. Before his initial reanimation, however, Hershel or Otis placed him inside of the barn, along with his mother, Annette.

"Bloodletting"
Hershel mentions that he lost both his son, Shawn, and his wife, Annette, during the outbreak.

"Save The Last One"
Maggie relates her sadness over Otis's death to her sadness over the deaths of Shawn and Annette. We later see pictures of him and Annette hung on the refrigerator in the farmhouse.

"Secrets"
Shawn and Annette are revealed by Hershel to be zombies in the barn. Maggie brought up his name, along with those of Annette and some of their neighbors, to Glenn when they were gathering supplies at Steve's Pharmacy.

"Pretty Much Dead Already"
Toward the end of the episode, Shane opens the doors of the barn. As the zombies exit, the remaining Atlanta Camp Survivors proceed to kill all of them, Shawn included.

"Nebraska"
Shawn, along with his mother, Annette, and Sophia are buried under some trees next to the barn.

Killed By
Shawn and his mother, Annette, were both bitten and infected by walkers when they arrived back at the farm. Over a period of time, he becomes a walker and is taken to the barn.
 * Walkers

After Shane forces the barn open, the walkers inside proceed to exit. Systematically, they are shot and killed by the group of Atlanta Survivors. It is unclear which survivor provided the shot that extinguished the zombie Shawn. However, due to the fact his head-shot was executed by one a single bullet from handguns rather than the scatter-rounds from the shotguns, it was either Shane, Andrea, or T-Dog.
 * Atlanta Survivors

Beth Greene
She is assumed to have cared for her brother since when he was killed in the barn shootout, she was crying but did not run to her brother's corpse. Shawn was also Beth's only "playmate" when Maggie went to college

Patricia
It is assumed Shawn and Patricia would have got along, assuming the two worked on the farm together and being neighbors.

Trivia

 * In the TV Series, Shawn is Hershel's stepson. However, in the Comic Series, he is Hershel's biological son.
 * In the Comic Series, Shawn was Hershel's eldest child, but in the TV Series, he is much younger than Maggie.
 * Shawn is one of nine named characters in the TV Series to be introduced as a walker, the others being Summer, Hannah, Doug, Annette Greene, Louise Bush, Wayne Dunlap, Erin, and Penny.
 * Shawn Greene is one of five teenagers to die in the TV Series, the others being Jimmy, Randall, Jody, and Ben.