Dr. Laszlo Kreizler is an alienist, or criminal psychologist called upon by Theodore Roosevelt to investigate some mysterious murders in 1896 New York City.

Holt Hyde is a student in Monster High. He is the alter ego of Jackson Jekyll, his normie version. He transforms into Holt Hyde whenever he hears loud music, that's why he is always listening to music on his headphones. He has blue skin and fiery red hair