I'm not entirely set on who I would want to go with, but I mentioned to Truth that at the forefront of my considerations were Ace Attorney's Sholmes or Rain Code's Yuma (and Shinigami).

By the way [@TruthHurts], are you thinking the characters would be sort of whisked away into this mess or maybe it would be more fun if they found a thread of mystery leading to it and ended up... wherever they end up because of that? Also are you thinking arcs will take place in like a nebulous world or be media-related arcs? For example a case set in Scooby universe, or in Revachol, or at Hope's Peak, etc?