Mahoutsukai no Yakusoku

On a windy and moonlit night, Akira enters their apartment's elevator and exits into a world full of magic and danger, where humans and wizards struggle to coexist. Chosen wizards known as the Sage's Wizards fight a yearly battle against their planet's moon and their only hope of success lies within the summoned Sage from another world. Akira is that Sage. But... The last battle was catastrophic, leading to half of the chosen wizards being destroyed and old enmities to reawaken. Now, Akira must find a way to build a bridge of trust between the wizards and humans of the world, while preparing the new Sage's Wizards for the battle to come.