The Butterfly Wings are a style item for the back costume slot.
They are not available in-game, but exclusively from the marketplace as DLC.
While the player is in the air, the wings swing back and forth.
|Costume Style Sets - Iconic Battle Suits|
|Head List - Face List - Shoulder List - Chest List - Hands List - Back List - Waist List - Leg List - Feet List|
|Head Styles - Face Styles - Shoulder Styles - Chest Styles - Hand Styles - Back Styles - Waist Styles - Leg Styles - Feet Styles|
|Costume listings include both, stats-enhancing armor and simple style items|