Fire Mage Reborn — John Forrester

For centuries, mages perfected magic at the Order of the Dawn. Mastery over fire, wind, and storm. They live in the last free city in a world plagued by dark sorcerers. Talis Storm and friend Mara discover a terrible secret: the Jiserian Empire has targeted their city for attack. An army of undead soldiers. Flying necromancers. None have ever survived. 

When a surprise aerial invasion hits the Order's temple, Talis casts fire magic for the first time, but his spell is wild. Sorcerers try to capture Talis and Mara and they flee into the temple crypts. Awoken from an ancient rest, a fallen champion slays the sorcerers and gives Talis a legendary map. The map leads them on a quest to discover the lost temple of the sun.To save his city, Talis must discover the power of magic locked away inside the ancient temple and become a true fire mage.