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.
Ba Jin (1897-1966) was a famous Chinese writer, translator, ideologist and social actician. His works have a variety of styles, ranging from profound realism to beautiful romantic poetry and prose. His masterpieces included Home, Spring, and Autumn. Cato Dato (1889-1966) was a famous Spanish poet and translator. His works varied from poems, novels, and plays to prose and translated works. His masterpieces included Don Quijote and Isabella. Liang Xiaosheng (1948-) was famous in China. His works had a strong sense of social responsibility and a critical spirit with the theme of social reality. His masterpieces included Alive and Xu Sanguan's Blood Selling Chronicles. Bach van der Beichen (1770-1827) was a famous German composer and pianist. His works have a variety of styles, ranging from classical music to romanticism and impressionism. His masterpieces included the Fifth Symphony, Moonlight Sonata, Choral Symphony, and so on. These works had a profound impact on world music.
It's hard to pinpoint exactly where Gojo is at any given time in the manga. His whereabouts change as the story progresses and different scenarios unfold. It could be in a supernatural realm, a mission site, or interacting with other characters.