Aerial is a wind spirit who forms a profound bond with Taichi Nishimura after his journey to another world. Initially introducing herself as a simple wind spirit named Aerial, she later unveils her true identity as Sylphy, Queen of Wind Spirits, coinciding with Taichi's growth in magical prowess.

Her appearance features platinum green hair, teal eyes, pointed elf-like ears, and four feathered wings. She manifests as a youthful fairy figure adorned in a green hagoromo-style sash, wing-shaped hair accessories, and three diamond markings on each leg.

Aerial exhibits fierce loyalty and protectiveness toward Taichi. She voices remorse for her initial inability to aid him due to summoning constraints, vowing never to abandon him. Before their formal pact, she communicates telepathically and temporarily shares her power during Taichi's clash with Cassim's Red Wolf.

Their bond deepens after Anastasia's death, when Taichi fully accepts his abilities and contracts with Aerial. As their connection intensifies—especially during a pivotal battle outside the royal capital—Aerial evolves into her true form: Sylphy, one of the Four Great Spirits.

Her capabilities encompass absolute mastery of wind-element magic, including spells and enchantments for atmospheric manipulation. This control proves decisive in conflicts such as defending Azpire from monster invasions and quelling battles against berserk soldiers.

Throughout their journey, Aerial acts as Taichi's magical companion and emotional anchor. Her evolution mirrors his progression in harnessing his own powers.