Princess Crystal, also known as Cristel, serves as the primary antagonist from the kingdom of Megaronia. She initiates a quest for global domination after rediscovering the Sacred Book from the conquered land of Eija. This ancient text contains legends revealing the location of the all-powerful vessel Ellcia, equipped with ultimate weaponry capable of subjugating the world. Her objective centers on securing this ship to consolidate her power.

Her background involves leading Megaronia's military expansion, resulting in Eija's subjugation. During this conquest, she took the heir to Eija's throne hostage, intending to exploit his lineage for political leverage—demonstrating her strategic use of captives for imperial goals.

Throughout her pursuit of the Ellcia, she commands Megaronia's forces and employs the Sacred Book's knowledge to locate the ship. Her methods are characterized by ambition and ruthlessness as she seeks to eliminate opposition, particularly a group of pirates attempting to thwart her. Her antagonistic role is defined by the conflict between her desire for total control and the resistance against her.

Her relationships remain adversarial, primarily opposing the pirate crew led by Captain Eira, who aim to rescue the Eijan prince and prevent the Ellcia's weaponry from being unleashed. No familial ties, personal history beyond her imperial role, or redeeming qualities are documented. Her narrative trajectory concludes without achieving world domination, as the pirates disrupt her plans.