Shoreseeker (The Farshores Saga Book 1) by Brandon M. Lindsay

SPFBO6

The #1 Epic Fantasy in Japan It was supposed to keep them safe. For six hundred years, Andrin’s Wall protected the remnants of humanity from a scourge that devastated them: beastly monsters called the sheggam. But centuries of relative peace have relegated the sheggam to myth and superstition. Tharadis, the Warden of the independent city Naruvieth, must protect his people and their homes from threats more immediate than ancient legends. The Council of the Wall aims to finish building the Runeway, a magical construct spanning the whole of the Accord, no matter who gets in their way. But after a knight with sheggam magic flowing through his veins seeks protection in Naruvieth, Tharadis uncovers a menacing secret: the Runeway itself is built from sheggam magic, magic that isn’t supposed to exist on this side of Andrin’s Wall. Not only must Tharadis confront scheming politicians, rogue knights, and ominous prophecy, he must draw his blade for the greatest battle humanity has ever faced. For the sheggam are already here.