Arche Soldiers are armored infantry with augmented mobility. As their name suggests, these blue crystal-armored troops—commonly called aether-armored troops—are the product of their blue crystal-based civilization. These valiant warriors wear powered exoskeletons covered with blue crystal alloy. Though still fueled by Y-thermoses, they are smaller than pseudo-Ymirus mechs and other forms of transport, and therefore cannot carry a blue crystal steam engine. Instead, their armor is powered by crystallis hydraulics, the piping for which runs through their armor in order to provide power for the entire exoskeleton. Wielding blue crystal kinetic blades, Arche Soldiers are capable of facing down guns and artillery. Each of their battle squads is made up of individuals with different loadouts. 

In kingdoms with battle strategies centered around kinepolises, combat modules like city gates and watchtowers can carry their assigned battle squads on offensive operations. The ability to pair battle squads with combat modules possessing complementary capabilities has given rise to extremely effective battle tactics.