Tycho Science pilots powerful mechas called Buster Machines as a Topless within the elite Fraternity, humanity's defense against space monsters. She has purple pigtails, red eyes, and unique earrings—one crescent-shaped, the other featuring two spheres. Initially piloting Soixante-Six (Buster Machine #66), a close-combat unit armed with guided Buster Orb projectiles, she later commands Quatre-Vingt-Dix (Buster Machine #90) after Soixante-Six's destruction. This machine wields a Buster Racket melee weapon and unleashes Buster Smash, a freezing attack achieving temperatures below absolute zero.

A childhood trauma defines her cynicism: Tycho befriended a terminally ill boy, promising to save him with her Topless powers. Her failure to prevent his death bred disillusionment, leading her to resent the abilities' limits—unable to heal sickness, stop wars, or reverse death. This bitterness fueled a fierce rivalry with fellow pilot Lal'C Mellk Mal, whom she mockingly dubbed "Princess." Tycho prioritized surpassing Lal'C's combat records over mission success, resulting in reckless actions during a Jupiter defense operation. This caused Soixante-Six's loss and compromised humanity's defenses.

Tycho's cynicism gradually unravels through Nono's idealism and confronting her past. In a crisis, believing her powers meaningless, she discards the guilt-symbolizing earrings to protect children. This selfless act awakens Quatre-Vingt-Dix, responding to her resolve. Piloting it, she repels a space monster swarm at Jupiter, acknowledging her actions served personal fulfillment, not obligation.

Nono later returns the earrings, which Tycho keeps—accepting her past without its burden. Ten years after the final space monster's defeat, she retires from piloting and works peacefully as an environmentalist alongside former Topless comrades.