How about an epic showdown between Ayano and Oka involving summoning demons? Well, that might be a bit far-fetched. Oka's weakness seems to be her susceptibility, so a unique approach to eliminate her could involve demons in some way. However, she's quite strong, so it's unlikely that Ayano could simply drown her unless she increases her stats and joins the Occult Club herself. The students in the Occult Club use a specific room before and after school, and Ayano could participate in the club's activities and meetings if she becomes a member. I'm sure Oka would be pleased to see anyone showing interest in the Occult Club. It could be relatively easy to corner her and eliminate her if she's not with her occult club members. Just imagine, why not go to the demon world and summon some powers?
As for Kizana, her weakness could be greatly affected by gossip and bullying, considering her aspiration to become a popular girl in school. Osoro, on the other hand, may try too hard to please others in her gang and be a strong leader, which causes her to forget that she's more than just a tough girl. It's possible that she has a good relationship with someone. As for Asu, her weakness might lie in her belief that everyone is inherently good and capable of doing their best in any task given. Can you blame her?
Rin is the person Ayano used to blame for her parents' death. Initially, I didn't like Kokona, but after watching some Yandere Simulator YouTubers, especially LaurenZside who got me hooked on the “best friend” thing, I began to appreciate her character. The mission will consist of 10 levels, and each level will introduce a unique step that Ayano needs to complete. Ayano must be sneaky, clever, and patient to accomplish this task. Ruining the little relationship between two characters would require Ayano to be sneaky, skip classes, and expose the teacher as a predator. However, the main story mode(s) will not include any randomness. Completing this mission could be quite challenging, as Ayano shouldn't be spotted by anyone. However, it becomes much easier if she's a part of the drama club or in disguise. By the way, the game is partly inspired by the real-life serial killer Ed Gein, if you're interested. Along the way, Ayano is assisted by a character similar to Info-chan, who acts as a merchant selling useful items. Ayano needs to get involved when they exercise together and make it appear as if Asu is a terrible workout partner. Muja's weakness is clearly her clumsiness, which can work to Ayano's advantage.
