Index of Happy Death Day: A Comprehensive Guide to the Time-Loop Slasher
Introduction
Film 1 Killer (Lori Spengler): Tree’s roommate. The motive was jealousy over an affair with a married doctor. The Babyface costume was chosen because it was the school mascot.
Film 2 Killer (Gregory Butler): In the alternate dimension, the killer is Tree's professor, Gregory, working with a version of Lori. The motive in the sequel is to cover up an affair and steal the scientific discovery for themselves.
