Luca serves as the enigmatic navigator and seer of the Bentenmaru, balancing technical mastery with an aura of mystery. Her appearance shifts across adaptations: the anime portrays her with black front-bangs, piercing purple eyes, a violet dress, an eyepatch, and a floral-feathered headband, while the manga features dark blue-purple hair, oversized earphones, and a sleek suit with a fur-lined collar and cloak. Her signature tool—a crystal ball doubling as a monitor—anchors her mystique and practicality.

Emotionally detached and laser-focused on her duties, she avoids casual interactions, communicating through cryptic phrases like "I see it...," which unsettle or frustrate crewmates. Yet under extreme pressure—navigating spatial distortions or cosmic storms—fleeting cracks in her composure expose glimpses of humanity.

Her origins remain shrouded, though she joined the crew following Ririka Kato’s departure. During Marika’s training, she delivered blunt, precise evaluations. In the Golden Ghost Ship crisis, her ambiguous warnings proved vital for surviving black holes and proto-planetary hazards.

When a virus ravaged the ship in the Hakuoh Pirates arc, she maintained icy calm, co-authoring emergency protocols while masking irritation at technical failures. Later, an android duplicate infiltrated the Bentenmaru during the Pirate Hunter arc, prompting a crew showdown. Post-resolution, she reappeared from an interrupted leave, offering rare, terse thanks to Kane—a flicker of camaraderie.

The *Abyss of Hyperspace* film thrust her into a subspace collapse, where her rapid calculations pinpointed unstable routes and enabled emergency jumps. Though her character arc stays subtle, dry humor surfaces in crew banter, and minor reactions—a raised eyebrow at chaos, a quiet game—hint at layers beneath her aloof facade. The crystal ball, both tool and prop, epitomizes her dual identity: a technocratic seer melding precision with performative intrigue.