12. Team Rick vs. Team Governor
From: Walking Dead #48
Walking Dead's long-running Prison Saga came to a stunning conclusion when a number of characters were killed off during a battle between protagonist Rick Grimes' clan of survivors and the demented Governors' army from Woodbury.
The battle between these two sides had been simmering for more than a dozen issues. The Governor had initially captured Rick and some members of his group, including the sword-wielding Michonne, a handful of issues earlier. While holding them captive, the Governor chopped off Rick's hand and brutally raped and beat Michonne. Michonne would get her revenge, gouging out the Governor's eye in the process, but Rick knew that a confrontation between both sides was inevitable.
After lulling Rick's group into a false sense of security, the Governor storms the prison haven with tanks, breaking down the gates. During the battle, Rick's wife Lori and infant daughter Judith are both killed by one of the Governor's supporters, Lilly. Lilly is so dismayed by the fact that she killed a baby, turns her gun on the Governor, shooting him in the face and leaving his body to be devoured by a gang of zombies. Rick's friend, Herschel is also killed off.
By the end of the arc, the Walking Dead's status quo was thrown into so much upheaval, the series was practically starting from scratch, with only a handful of its original characters still around. Meanwhile, the Prison Saga storyline and subsequent battle was the primary focus of the most recent seasons of AMCs The Walking Dead, by far the most successful comic book-turned-television show in history.