Ghostopia, Chapter 49: Skeletons In The Closet

So it was possible. Hearing Nelson talk about how he once escaped from Ghostopia made Mortie's cause seem less far-fetched now. More so when Nelson was the one who'd planted the most doubt in him.
"Once we had all four records, it was just a matter of taking care of the gatekeeper. Good thing he was smart and joined us at last. Otherwise James would've had him killed."
"After we went through the other side of the bookcase, we could each see the places where we died. It was like being in a dream; you can just see it, but you're not really there. The final thing to do then was to look for fear."
"Fear? Why fear?" Darren asked.
"That's how Ghosts come back to the living world - it's a gateway of sorts. Once someone in the group comes across fear, everyone focuses on it and boom! Welcome back to life."
Nelson stopped, nodding his head repeatedly. Something was troubling him.
"You know how the rest of the story goes, don't you?"
"Uh-huh," Darren nodded. "You couldn't make yourselves human again, and almost everyone got Exorcised."
"That's right," he murmured. "Just three of us. Lucas, me, and another girl. But there's something else you don't know."
He paused again, as though for dramatic effect.
"We killed someone."
Darren frowned, trying to fathom the impact of the sentence. "You mean, in the living world?"
Nelson stared at the ceiling for several seconds. "Yes. In the living world."
"But...how? Weren't you powerless as Ghosts?"
"Come," he stood up. "Let me show you something."
Darren followed him out of the room to some attic downstairs. He rummaged through a few neatly-stacked boxes, finally stopping at one which was heavily taped up. He carefully removed the sealing and opened the lid. It was filled with blank papers.
"Ah, still there sitting pretty," He smiled, peering into the box after he took out the papers. "I don't think I've seen it once in three years."
"What's it?"
Nelson carefully held up a glowing green prism. "Say hello to my ExorPrism."