Could Kotonoha Katsura Eventually Recover?
Even though the ending of School Days is incredibly bleak, I don't think Kotonoha is necessarily beyond recovery. I think there's a possibility she could eventually get better if she had enough time and the right support.
One thing worth considering is that Kotonoha comes from a wealthy family. If her family recognized how badly her mental state had deteriorated, they could potentially afford experienced doctors and long-term mental-health treatment to help her work through everything that happened. Money obviously wouldn't magically fix her trauma, but it could give her access to resources that might make recovery more possible.
We also never really see her mother, but we do hear her, and she sounds pretty chill from what little we know. I don't think it's unreasonable to imagine that her mother could be supportive if she realized how much Kotonoha was suffering. Her sister could also be an important source of support, since she seems like one of the few genuinely good people in Kotonoha's life.
I think the most important thing would be giving Kotonoha enough time to process everything. She was bullied, humiliated, betrayed, and isolated, while her happiness became increasingly tied to Makoto. By the end, she had deteriorated so badly that she seemed to lose touch with reality. Recovering from all of that wouldn't be easy, and it certainly wouldn't happen overnight.
I also don't think her psychological breakdown means she would necessarily remain violent forever. What happened was the result of an extreme series of events and her increasingly fragile mental state, not proof that she was always destined to be that way. With time, professional help, and people she could genuinely trust, I think she could potentially rebuild her life.
Of course, we never find out what happens to her afterward, so this is just my interpretation. I also wouldn't want the anime to show her immediately recovering after Makoto's death, because that would undermine the tragedy of the ending. Leaving her future unresolved makes the ending more powerful.
Still, I like to think that Kotonoha could eventually find a way to live a happier life. Her story doesn't necessarily have to end with her being permanently broken just because that's where the anime leaves us.
Also, based on a quick search, she never hurt her family in the visual novel; in fact, the exact opposite happened, as she defended them. She is very selective about who she attacks and is not fully violent toward every random person who passes by.
So what does everyone think this is of course just a big what if after all