Here's why Shane caused Otis' death on The Walking Dead season 2. The Walking Dead is based on Robert Kirkman's acclaimed graphic novel, which follows protagonist Rick Grimes as he awakens from a coma to find the world overtaken by swarms of zombies. Rick sets out on a quest to find his wife and son, and the series examines what happens to humanity in the face of a zombie outbreak. The Walking Dead eventually came to a surprise end with issue #193 in 2019, which served as something of an epilogue.
The Walking Dead TV show debuted in 2010 and cast Andrew Lincoln as Rick. The series drew a lot of inspiration and key storylines from Kirkman's comic, but it was never afraid to carve its own path. Characters who died early in the show lasted way longer in the comics, and visa versa. The show soon became one of the biggest on TV and spawned spinoffs like Fear The Walking Dead and various video games and novels. Lincoln left the series during season 9 but is set to return as Rick in a forthcoming movie.
The Walking Dead season 2 was criticized for its lack of action and zombie attacks, which was seemingly the result of budget cuts by AMC before production commenced. Nevertheless, the second season was an important one in terms of character development. This is especially true of Jon Bernthal's Shane, Rick's best friend and partner. Shane took Rick's wife Lori and their son Carl to safety after he fell into a coma, and thinking he was dead, Shane and Lori started an affair. Rick's resurrection causes him to resent his former friend - especially when he learns Lori is pregnant and the baby is likely his.
A key turning point for Shane is The Walking Dead season 2 episode "Save The Last One." This sees Shane and Greene ranch hand Otis trapped in a school following a mission to find medical supplies for a dying Carl, who Otis accidentally shot. The duo brave swarms of zombies and work together to escape, but both suffer leg injuries. They limp as fast as possible while carrying the heavy medical gear, and start to run out of ammo firing at pursuing walkers.
Realizing they likely won't make it together, Shane shoots Otis in the leg with his last bullet. He then grabs the supplies off Otis who is ripped apart while Shane makes his escape. This was one of The Walking Dead's most shocking scenes in its early seasons and while audiences could understand the cold logic of Shane's actions, it marked a moral spiral that he'd never recover from.