Return of the Banished Archmage is a Manga/Manhwa/Manhua in english language, Action series, english chapters have been translated and you can read them here. You are reading chapters on www.mgeko.cc fastest updating comic site. The Summary is

“I will have my revenge, no matter what.”

Three thousand years ago, in an ancient Kingdom of Magic, Asuma, an archmage of unrivaled skill, saved the world from otherworldly invaders and became a savior. Yet, fearing his power, the king banished and ultimately killed him. However, Asuma’s soul returned to modern times.

In the Magic Academy, simply known as the “Academy,” where modern magic combined with science is the standard, Asuma is reborn as a student named Shiobana Asuma. He vows revenge against the descendants of those who drove him to his death all those years ago. Combining his mastery of ancient magic with modern, science-based magic, he develops unprecedented hybrid magic…

“For mere students aspiring to be mages in this era to challenge me—you’re ten thousand years too early.”

...and thus begins his tale of his revenge.