Toge Inumaki is important too. His special cursed speech ability makes him stand out. Also, the principal of the school, Masamichi Yaga, is likely to be important as he is in a position of authority and has an influence on Gojo and the other students. There could be other characters like the members of different clans that also play roles in the complex web of the story.
If you like the novel " Night of a Hundred Ghosts," I can recommend you a few similar works. Here are some recommendations for similar novels:
1. " Corpse Ghost Immortal ": This is a Xianxia fantasy immortal cultivation novel, which also contains the elements of a hundred ghosts and immortal cultivation.
2. " I Set Up a Night of a Hundred Ghosts in the Ninja Realm ": This novel also contains elements of the Night of a Hundred Ghosts, but the story takes place in the Ninja Realm.
3. " Ghost Tales of Tokyo, Second Month ": This novel is a fantasy novel. The plot involves the night of a hundred ghosts and the elements of clearing ghost stories. It also takes place in Tokyo.
4. " From Kappa to Tokyo Night Walk " was also a fantasy novel. The story involved demons, the night of a hundred ghosts, and the plot of the protagonist's incarnation.
Please note that there are some similarities between the novels recommended above and Night of a Hundred Ghosts, but the specific content may be different. I hope these recommendations can satisfy your reading needs.