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.
It can be a plot device to increase tension. For instance, if the main character is about to be blindfold - executed, the readers will be on the edge of their seats.
In story fiction, blindfold execution can be a very dramatic device. It often represents a sense of helplessness and the ultimate inhumane act. For example, in some historical - based fictions, it shows the cruelty of certain regimes. The blindfold itself adds an element of mystery, as the victim is not able to see their fate approaching.
Once upon a time, there was a girl named Lily. Her friends decided to play a tickle game. They blindfolded Lily. As soon as the blindfold was on, her friends started to tickle her softly. Lily burst into laughter. She tried to grab her friends' hands but couldn't see. It was a really fun and silly moment for all of them.