Mototensai Eiyuu, Academy de Yarinaosu

Kyoichiro Misato, leader of the strongest adventurer group, Golden Seekers, is betrayed by his comrades and trapped inside a gate. On the brink of death, he uses his powers to be reincarnated as Kyosuke Asai, a student mocked for being Attributeless, with seemingly no power at all. Kyoichiro, however, knows it holds potential beyond even the legendary Time attribute. Now in Kyosuke’s body at the adventurer academy, he begins to develop that potential and vows revenge on those who betrayed him.(Source: WEBTOON)