Astorga, alternately known as Aphrodia, is the adopted daughter of General Galvez (also called Gattler), who seizes control of the polluted planet S-1 through a military coup. After her father's ascension, she rises to a key command position within the Aldebaren Army, leading efforts to conquer Earth. Her relentless pursuit of vengeance stems from a personal trauma: her biological brother's death at the hands of Marin Reigan during his escape from S-1. Despite her authority, she contends with pervasive gender-based discrimination and criticism from male counterparts in the Aldebaren hierarchy, especially following operational failures.

Her dynamic with Marin evolves during the Earth conflict, shifting from hatred toward a complex interplay of mutual understanding, unspoken trust, and situational cooperation—underscored by unresolved romantic tension and emotional conflict, all strained by past wounds and opposing loyalties. Her arc escalates as General Galvez deploys artificial suns to melt Earth's polar ice caps, triggering catastrophic tsunamis. Witnessing the devastation alongside Marin, she confronts the horrific fallout of her father's campaign.

In the televised series' conclusion, she survives the global flooding but faces an ambiguous, desolate future amid Earth's ruins. The film adaptation diverges: during a climactic duel with Marin within the collapsing Algol fortress, she is seemingly killed by falling spaceship debris while drawing her weapon. A post-credits scene hints ambiguously at their spiritual reconciliation beyond death. The uncut Japanese film version adds a surreal, previously excised scene of an attempted rape, intensifying the complexity of her experiences. Her narrative remains intertwined with environmental motifs, particularly Marin's symbolic longing for a "blue sea"—representing purity and peace that her actions inadvertently oppose.