"Walkers," he said, as he focused on Judith for a moment. "Some people here call them zombies. The undead." He didn't particularly care for talking about his world, but he would if asked directly about it. Like Ronan had. He understood that his world was different than other people's worlds. A lot of people's worlds were different.
"I am not completely sure how it happened, but an apocalypse happened. Even if you died, without being bitten or scratched by a walker, you had a chance of becoming one. The only way to be sure you didn't become one was if you took a bullet or something to the head."