Hassu, nicknamed Hass, remains a steadfast companion to Rikka Takarada, often appearing alongside Namiko. She playfully ribs Rikka about her bond with Yuta Hibiki, especially after spotting the pair at a convenience store. Post-kaiju attacks in Tsutsujidai, her recollections of erased events and people reset alongside the town’s restored reality. Once Alexis Kerib is vanquished, her existence stabilizes without further memory disruptions.

Measuring 155 cm, she sports long black hair cascading in a side ponytail fastened by a green scrunchie, paired with vivid blue eyes. A white flu mask persistently conceals her lower face, worn without illness, and she bristles at inquiries about her concealed features. Her outfit comprises a white shirt tucked into a black skirt adorned with a dark pink bow, a blue towel displaying "ravage" alongside a feline graphic, long white socks, and dark brown shoes. On a mountain excursion, she layers a blue bikini under an open coat and occasionally secures her hair in a bun.

Her aesthetic nods to Transformers’ Shattered Glass Soundwave, her mask mirroring Soundwave’s mouthplate, while her towel echoes Ravage, his cassette ally. This theme continues through her YouTube alias "Hassun," aligning with Soundwave’s communications expertise. Her name potentially originates from Hasbro, Transformers’ creator.

Though calmer and more levelheaded than Namiko, she joins in good-natured mockery of Rikka. A duet with Namiko, "Oh! My hero!," features on the SSSS.GRIDMAN BEST ALBUM but lacks a standalone character-song release. Subsequent films or spin-offs preserve her defined role without expanding her backstory.