There were many kinds of hand gestures for Gotto Gojo, including greeting, teleportation, and domain expansion. However, the specific description of the gesture was not found in the search results provided. Therefore, based on the information provided, I am unable to accurately answer how to do the gesture of Gojo Guru.
Nope, Marin and Gojo don't end up as a couple in the manga. The manga follows a different narrative path for their relationship, concentrating more on other aspects of the story and character growth.
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.