Catherine, one of three identical Royal Sisters central to the Pirate Guild’s plot to conquer the artificial planet Myrus, begins her journey as a gentle school teacher marked by her quiet, nonviolent nature. Framed for crimes she did not commit, she is incarcerated on Sido, only to be “rescued” under the hidden mental dominion of Crystal Bowie—a Pirate Guild enforcer with a body forged of glass and gold. Compelled by Bowie’s control, Catherine betrays her sister Jane, inadvertently causing Jane’s fatal wounding.

Liberated from manipulation, Catherine sheds her timidity, ascending to rule Myrus as queen. In her defining act, she pilots the planet into a sun to thwart the Guild’s scheme to obliterate the Seventh Galaxy, her sacrificial death merging her spirit with her fallen sisters in a cosmic union echoing their bond.

Though her sisters’ map-like tattoos—a fragmented guide to a galactic treasure—tie the trio to legacy and power struggles, Catherine’s direct involvement in this thread remains peripheral, her narrative instead crystallizing resilience and redemption through selfless love.