From Manga Abyss: Which to choose, the country or my friend--!? The "Continent of Cruzon", a world where people are born with magic. Lygatto, one of the rare people "without magic" in this world, is getting swallowed up in the whirlpool of a massive war. With Lygatto as the core, four close friends are connected by cruel fate in a spectacular war tale!!!
In the continent of Cruzon, an impending war between the Kingdom of Krishna and the nation of Athens is brimming. The people of this land are able to wield the crystals from the ground for whatever purpose they desire. Yet one person, Lygatto Arrow, is not. He is an "un-sorcerer", a person unable to wield the crystals. But this characteristic will enable him to pilot an ancient mecha, one strong enough to put up a fight against the invading army of Athens.
Summary by solitaryCross
From Baka-Updates: Rygart Arrow is the only one in his world who lacks the inherent ability to power up quartz, the energy source that makes all of the machines run. Nevertheless, he's pretty well connected. The King and Queen of his country of Krisna happen to be old college friends. But so is Zess, the guy who is leading the army of a neighboring kingdom in an attack on Krisna.
How did it comes to this? There's little time to ponder the implications as an army in giant, mechanized battle suits attacks. Arrow just feels like he's in the way - until he comes across a powerful, ancient mech that no one has yet to be able to figure out how to run. But his natural affinity for the suit's operating mechanism may just turn Arrow into the most important player of all.