I'm getting the feeling that their insanity is topical. If their attention is diverted, they become moderately sane. But since they're all fucking crazy, they'll find some way for the madness to escape again.
Flan's always been sane. The comic's split between the psychopaths (Yuuka, Flan, Chen), the unhinged (Keine, Ran), and the victims (Tewi, Marisa). Chen's the anomaly, she started aout as a victim, but Yuuka's been teaching her sadistic tendencies to protect herself.
It's all internally consistent, quite crazy, and a little sad.
Stop! Do you want to die!? It's too late for her! Run away! Hurry!!If you are reading this, I am already no longer of this Earth. 2nd Place - Cirno
"It was fun."I don't need that. You're mistaking torture.Cheeeeeeeen!!!So it's finally revealed it was fixed all along.But in any case, you did well. I'll reward you with a kiss.I'll reward you with a kiss.Resubmission - Tewi
"Chen is cute."Huh, where? That's scary.I'll reward you with a kiss.3rd Place - Daiyousei
"I'm innocent."I wonder how a child raised by such an adult would turn out. What a nightmarish experiment.Lay off already.*smooch*I pray that no more victims (the journal stops here)Oh, there she is.Special Award - Flandre
"I'm looking back on my time as head jailor."I received a comment from the head of the judging committee, Ms. Yakumo Yukari.I don't want it, screw off! Don't come any closer, stop... Stop Kamishirasawaaaaaaammmmph!!Let's see, "It was too frightening to read, but it's unmistakeably Chen-chan's, so first place."In your summer break contest of independent experiments, Chen won first place with her "process of the damage to the mind and friendship from separating fairies into the roles of jailers and prisoners."