Fastener is a supporting character in the anime series Panty & Stocking with Garterbelt. He is the loyal pet and companion of Stocking, resembling a small white dog with a zipper running along his back. Although he doesn't speak, Fastener often assists Stocking in battles by transforming into various weapons, specifically a katana. His quirky appearance and comedic behavior provide comic relief, and he plays an important role in helping the Anarchy sisters fight evil spirits throughout the series.