Sylphiette

Sylphiette is Rudeus' childhood friend who is part human, elf, and beast race.

In her youth, she had short green hair and elfish ears. Her tomboyish appearance initially made Rudeus believe she was a boy.

Following the Teleport Incident, during which her hair turned white from mana exhaustion, she became Princess Ariel's personal bodyguard under the alias Fitz.

After the Teleport Incident, her hair became white. Although she grew to have a more feminine body, her slender appearance combined with her apparel made her look more masculine. She also wears white gloves as her permanent accessory starting from Season 2.

She is Rudeus' first wife and gives birth to their daughter Lucy and son Sieghardt. She is one of the three goddesses Rudeus worships in his religion. A cloth stained with her virgin blood that serves as a relic for the Goddess of Love is enshrined in the basement.
(Source: Mushoku Tensei Wiki)