Black Knight Althea leads the Galfa army, a mechanical empire dedicated to humanity's extermination and universal conquest. Serving as a primary antagonist and elite guard under Emperor Galfa, Althea commands authority equal to the lunar fortress Spiral Castle. Althea pilots the black mecha Knight Gear Oger, a 28.5-meter, 401-ton counterpart to the protagonists' Dendoh, utilizing similar rechargeable batteries. Oger employs turbines for combat maneuvers, high jumps, and anti-gravitational flight. Althea wields specific Data Weapons: the Viper Whip attaches to the left arm for supersonic speed and whip strikes, while the Bull Horn equips the right arm with a pincer claw capable of crystal-wave assaults.

Althea possesses exceptional strategic intellect and combat prowess, consistently outmaneuvering foes through ruthless tactics and decisive leadership. Early encounters reveal a cold, calculating approach prioritizing mission success over emotion, frequently employing psychological warfare—like exploiting defeated protagonists' fears. This aligns with personality assessments labeling Althea ENTJ/INTJ (logic/strategy-focused) and Enneagram Type 8w9 ("The Challenger"), reflecting dominance and self-reliance. Yet moments of vulnerability and fierce loyalty to Galfa comrades complicate this typing. Initially dismissive of the young Dendoh pilots, Althea's perspective shifts upon witnessing their resilience and resourceful tactics—such as luring enemies into confined spaces—earning them reluctant recognition as "worthy opponents." This development culminates in visible frustration and audible disbelief when outwitted.

Background details remain sparse, though Althea's high rank and familiarity with Galfa history imply connections to the crusade's origin planet, Alktos. A significant plot element involves "Laser-Guided Amnesia," partially obscuring Althea's past. Relationships include commanding subordinates Witter, Absolute, and Gourmet, while tensions arise with Prince Subaru (Emperor Galfa's son) over their shared capability to pilot Ogre-class mecha. Despite the goal of universal domination, unwavering loyalty to the emperor occasionally conflicts with personal judgment as human adversaries persistently challenge Galfa's technological superiority.