Gomi Gojo's Territory Opening Gesture was an important element in the " Return of Curse ". Gotto Gojo's domain was displayed as 'Boundless Empty'. This gesture was to pull the enemy into the infinite inner side, forcing the enemy's brain to produce a large amount of information, causing the brain to lose its function and could only stand and wait for death. Although there was no specific description of the hand gesture, it could be speculated that the hand gesture was to expand the domain through a specific posture of the hands.
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.
The main character of "I Have a Spirit" received an ability after signing a contract. At first, a hand stretched out from his stomach and became the hand of a demon. Later on, he gradually gained the ability to sense emotions, as well as the powerful red light flowing on his body and the ability to absorb evil spirits. Finally, he gained the ability to see. I hope you like this fairy's recommendation. Muah ~๐