Nanatsu no Maken ga Shihai Suru: Side of Fire - Rengoku no Ki

Alvin Godfrey, a failure of a mage, entered Kimberly Magic Academy unsure of himself. Unable to cast a single spell, he was mocked by his peers. Yet he faced the darkness of Kimberly, made friends—and in time, became the student body president. Set five years prior to Reign of the Seven Spellblades, this is a scorching account of how Godfrey earned his famous nickname, Purgatory.
(Source: Yen Press)