The manga is about a mage guy who is the last man surviving with his parallel casting ability however using this ability need him to stay still.
He died in the end but before he dies he met the heroine who gives him his acceleration ability.
He is reincarnated back to his childhood, and during that time he starts attending academy at the 10th room (last rank room) because of his parallel ability is deemed inferior.
I think he is one of the few attending with a proficiency of lightning exceeding 80 and water around 75, and can transform his body into lightning.
The manga should be from Chinese (I remember it is full color).
- There is a loli headmaster that is a water god tier and one of the seven mages of the kingdom.
- Another one of the seven mages of the kingdom is a homosexual with wind god tier.
- The female lead is the descendent of the heroine who gave the MC his acceleration ability. The FL has a complication in her family because they want to marry her to another powerful family to allow the bloodlines to mix and produce the strongest passive ability.
- I think ML also has a partner which is a princess knight at a higher year in the school.
I remember that the later part of the manga is about a school tournament. It is a pair tournament (mage and knight) but the protagonist attends it solo as a mage.
In the semi-final, he fights against a female student that uses a flail as a weapon and in the final he fights with the female lead. In the end, this exposes that he has a god tier lightning attunement.