Ryū Lyon is an elf possessing sky blue eyes and green hair, originally golden-blonde before being dyed by colleagues at the Hostess of Fertility where she works as a waitress. Her exceptionally fair skin contributes to a fairy-like appearance. She stands 165 cm tall and wears a green maid outfit with a white headband and apron during work. Her former adventurer combat attire consists of a green hooded cloak, sleeveless top, bloomers or shorts, thigh-high brown boots, and gloves, with a sash holding her twin kodachi swords, Futaba and later Arvus Lumina. Once a member of the Astraea Familia and known as "Gale Wind" (疾風, Shippū), she achieved Level 4 status. Her Familia was annihilated by the monster Juggernaut during a conflict with the Evilus-aligned Rudra Familia in the dungeon, leaving her the sole survivor and driving her to pursue vengeance against those responsible. She employed traps and assassinations to dismantle Evilus, actions that led the Guild to blacklist her and the goddess Astraea to excommunicate her. She found refuge with Syr and Mia Grand at the Hostess of Fertility. Ryū maintains a calm and stoic exterior, masking deep loyalty and protectiveness towards those she cares about. This instinct compels her to intervene in dangerous situations involving friends, regardless of personal cost. She harbors significant guilt and trauma from her Familia's loss and her violent actions during her quest for retribution. Framed for a trader's murder on the dungeon's 27th floor, her innocence is uncovered by Bell Cranel and his allies, revealing ties to Evilus remnants like Jura Halmar. During this ordeal, Ryū and Bell are separated from their party and forced into the dungeon's deep floors. They confront the Juggernaut—the entity that destroyed her Familia—and face relentless threats from evolved monsters like the Moss Huge. This journey forces Ryū to confront her traumatic past, processing long-suppressed grief and guilt with Bell's unwavering support. These experiences catalyze her growth. She overcomes her inner turmoil, solidifying her resolve to protect others rather than dwell on vengeance. Visiting Astraea to update her falna results in an unprecedented double rank-up from Level 4 to Level 6 due to accumulated experience over five years. She joins the Hestia Familia as a full member, integrating more closely with Bell and his allies. Her relationship with Bell evolves from mutual respect to deeper emotional reliance, marked by moments where she draws strength from his heroism during their shared trials. Her character arc concludes with a renewed sense of purpose, shifting from isolation to active camaraderie within her new Familia.