Aisha Greyrat

Aisha is the daughter of Paul Greyrat and Lilia Greyrat and the younger half-sister of Rudeus Greyrat. Raised by her mother, Aisha's personality is more of an adult than those of her age, being able to act and speak in a manner of a maid. She is smart, manipulative, cunning, and cute. She has a playful personality and may have a brother complex as she sometimes makes suggestive comments towards Rudeus and has no problems being naked in front of him whenever they take baths together.

She later becomes the vice president and advisor to the Rudo Mercenary Company.
(Source: Mushoku Tensei Wiki)