Milza Kuches served as prince of Dartania, a nation on a small continent near Altirk and Haman. He murdered his own father, deeming him too weak to rule, and seized the throne. This act embodied his core belief that only strength and ambition justified leadership, principles guiding his entire life.

A tall man with long black hair, a matching beard, and piercing yellow eyes, he typically wore a dark, middle-eastern-style robe covering most of his head. Known as "The Black Swordsman," he wielded a short sword, favoring overwhelming force over strategy or defense.

His personality was ruthlessly ambitious, driven by a fanatical conviction that oppression and bloodshed were necessary to unify the continents. He disdained mercy or compromise, viewing kindness or defensive tactics—like those of Theo Cornaro—as weakness. He showed loyalty only for utility, often ignoring counsel, especially from tactician Terius, contributing to strategic failures.

Initially aligned with the Fantasia Union and supporting friend Villar Constance, he withdrew allegiance after Villar declined Union leadership. He then joined the Factory Alliance under Marrine, demanding her consent to sleep with him as proof of dedication to unification before pledging support. His forces later attacked Artuk by sea, where he slaughtered enemy ship crews single-handedly.

He met his end in a duel against Theo Cornaro. Defeated, Theo offered surrender of his Crest or death. Milza refused to yield or beg, choosing death to retain his honor. At death, his Crest had elevated him to Duke.

He left behind an unnamed adopted daughter; their relationship remained unexplored.