YMMV / Secret

• Complete Monster: Shinichi Mitomo, ever since he was young, held an incestuous lust for his younger sister, Ami Toono. Eventually, Mitomo attempted to rape Toono when the latter became a teenager, but was stopped by their father before being disowned. Later, Mitomo finds out that Toono was pregnant after she died in a bus crash during a school field trip. Wanting to make sure that the student who impregnated Toono is dead, Mitomo decided to kill every surviving male within the class solely out of envy for impregnating Toono before he could. Acting as the guidance counselor for the six surviving students of a bus crash, Mitomo spends the majority of the story attempting to manipulate the students into killing one another. When he believes that he successfully tricked Konno into killing Sanada and Amano, Mitomo meets up with Odzu and attempts to strangle him to death with a rope, gloating that he'll make it seem that Odzu committed suicide. When Sanada reveals that the deceased student, Shun Futami, was the one who impregnated Toono, Mitomo's only regret is that he didn't arrive at the school sooner to kill Futami himself.
• Narm: The true nature of Futami's death. He got into an argument with Kunikida when she confessed to him due to his grief over his dead girlfriend. Only, rather than telling her this, he remains weirdly obstinate until she throws the photo he kept as a Tragic Keepsake, after which he makes the baffling decision to climb over the railing to try and catch it midair, only to be accidently nudged into falling to his death. The incredibly stupid behaviour of the characters causes what is supposed to have just been a horrible accident to instead look a lot sillier.
• The Un-Twist: The identity of the culprit being Shinichi Mitomo is surprising precisely because he positioned himself as the mastermind from the beginning, and the reader was thus likely to think he was a Red Herring and that the real culprit was an unlikely suspect, as happened in the two previous works, Doubt and Judge.