Athena Tennousu 天王州アテネ

Athena is a daughter of the Tennousu family. She has mainly appeared in the manga. She has only been shown in the anime during a brief flashback where Hayate reflects on his first girlfriend. Her parents are presumed missing or dead, since she lived alone. She is Hayate's old girlfriend, as well as his first Mistress, whom he met 10 years ago. Since he was very young at that time, he called her "A-tan" for short.

In the 4th season she appears more frequent and becomes one of the tenants at Nagi's dormitory.