Mikata ga Yowa Sugite Hojo Mahou ni Toushite Ita Kyuutei Mahoushi, Tsuihou Sarete Saikyou wo Mezasu

"I don't need a worthless mage who can only use support magic. You're fired."
Alec, a court magician who supported the crown prince from behind the scenes, suddenly finds himself exiled from the royal court. Now jobless, he pays the magic academy a visit and runs into Yorha, one of his party members from his school days. Their renowned party once set a record in the royal dungeon—and now it's time to reunite and start a whole new legend!
(Source: K-Manga)