Rouge operates as part of the Red Snappers, an all-female elite unit within the NESS faction. The group comprises four sisters bearing names meaning "red" in various languages, with Rouge’s alias rooted in French. She pilots spacecraft in regulated non-lethal cosmic warfare, where teleportation safeguards prevent fatal outcomes.

Initially rivaling Yohko Yamamoto in both combat and pursuit of NESS commander Fluger von Meo-Toroll’s affections, Rouge frequently voices remorseful apologies while firing her ship’s weapons, revealing an internal struggle beneath her competitive exterior. Her trajectory shifts upon unearthing an egg-like relic tied to the Old Timer’s Inheritance, an ancient cross-dimensional power. The artifact propels her into a vision of Yohko’s memories, unraveling the motivations behind her adversary’s actions.

Empowered by this insight, Rouge confronts Yohko in a solo duel, staking Yohko’s exile to her original timeline on the outcome. Their clash halts abruptly when a malfunctioning space station intervenes, compelling joint efforts to avert disaster. This cooperation softens their rivalry into mutual respect, later tested in a decisive race won by Yohko, affirming their parity.

Rouge further engages in episodic skirmishes, such as competing for a planetary system prize won via crane game, blending tactical combat with absurdist stakes. Her journey intertwines with the Old Timer’s Inheritance’s destabilizing influence during universe-wide crises, positioning her at the nexus of factional strife and existential threats faced by NESS and its allies.