Harmony has fair skin, green eyes, and long red hair which she wears in a high ponytail similar to Shantae's. She wears a short white tank top exposing her midriff, separate white sleeves, light purple cuffs, white pants with cut-outs at the hips, and light purple boots. She is the tallest of the Half-Genies introduced in
Harmony first appears in Arena Town as a participant in the Half-Genie festival. She introduces herself to Shantae as the very first human-genie hybrid. When the Half-Genies gather backstage before the practice performance, she reassures them that they will be fine. She mysteriously disappears along with the other Half-Genies during the practice show.
Harmony is not seen again until Shantae rescues her in The Boiler. It is there she gives Shantae the Frog Fusion coin, allowing Shantae to instantly transform into a Sea Frog. After Shantae defeats the Angler Fish Siren, Harmony reveals the scrapbook left to her by the Guardian Genies. She says that each of the Half-Genies' mothers left a message for them, including Shantae's mother. Harmony confesses that sharing this scrapbook with the other Half-Genies was the reason she came to Arena Town. When asked, she happily agrees to share her magic with Shantae.
While Shantae retrieves a fusion stone, Harmony hears mysterious voices and follows them into the Mining Site, but loses track of them. When Shantae catches up to her, Harmony uses the fusion stone to merge their magic, granting Shantae the Quake Dance.
Harmony appears along with the other Half-Genies in Arena Town after Risky Boots activates the energy collecting towers. Rather than take back her magic, she entrusts Shantae with destroying the towers, and later with stopping the Flying Fortress.
After the Empress Siren is defeated, Harmony along with the other Half-Genies and Rottytops, arrive on the Flying Fortress. The Half-Genies take back their magic from Shantae, and then use their magic to take back the life force that the Empress Siren stole from them and Rottytops. When the Flying Fortress begins to fall, Harmony insists that Shantae should not stay behind to look for Risky, but ultimately wishes her good luck when she realizes Shantae is determined to stay.
In the ending, Harmony gives Shantae her mother's genie scrapbook.