Ayu is one of Heroes of the Sea Lifesavers characters. She is Natsumi's best friend along with Hijiri. Ayu is one of Hayate and Ayumu's friends who attends Shiomi.

She made an apperance in Hayate no Gotoku! Chapter 1 and Episode 37 in the flashback when Ayumu asked Hayate if he can take a photo sticker with her, but had no involvement in the main story.

(Source: Hayate no Gotoku! Wikia)