Anyone Can Die: The murderers and victims are randomly chosen, so literally anyone can die sans the Main Character.
Alas, Poor Villain: For every murder, the murderers have had a (somewhat) legitimate reason to kill with maybe the exception of chapter three.
All for Nothing: In both chapter one and two so far where Inori's secret gets revealed and Siyon turns out to not be the traitor. Later in chapter four when Mariko fails to bring back Root and five when Daniel's elaborate suicide plan to kill everyone fails.
Cruel and Unusual Death: In the form of the executions where the Psychologist, Inori, is played by his fears, the Seamstress, Kikuyu, is stabbed with a ton of sewing needles, the Runway Model, Jae-Eun, trips on her way down the aisle, and the Film Director, Mariko, gets smash in a movie screen.
Dark Secret: The motive for Chapter 1 consists of each student getting someone else's darkest secret. This leads to two murders out of paranoia and a lot of self-doubt leading to yet another murder.