Dead Space 3's latest developer blog "Dead Space, Dementia, and Punishing the Heroes," talks about the Markers, and how they affect protagonists Isaac Clarke and John Carver in different ways. Senior production designer Ben Wanat says Isaac's previous contact with the Markers will help him fight off the madness this time around. Carver won't be so lucky. He's going to experience nightmares.

"These manifest in the game as co-op-only missions," Wanat says. "During these missions, players will experience the world differently. If you play as Carver, you'll come across constant creepy reminders to his ugly past. If you play as Isaac, you'll get to see things as they really are which makes Carver's madness all the more apparent."

If you are a Dead Space lore junkie, you had best hope a friend picks up the game and is willing to play co-op with you. To see everything this story has to offer, you'll have to see it play out from both perspectives. For more on the Markers, dementia, and Carver's past, check out Wanat's blog entry.