Fluff is Glikko's sister, sharing a city apartment with him. She prefers domestic stability, contrasting with her brother's adventurous spirit. When Glikko decides to journey to the North Forest after learning of it from Pippo, Fluff is unconvinced and chooses to stay in their familiar home.

Overhearing Glikko and Pippo discuss the journey's dangers—foxes, hawks, and a neighbor's cat—Fluff intervenes. She creates an escape route from the kitchen, allowing Glikko to flee. She urges him to leave quickly when he offers her a chance to join him. After Glikko departs using their owner's hat to glide across the city, Fluff prays tearfully for his safety and success in reaching the forest.

Once Glikko successfully reaches the North Forest and establishes a new life, he asks Pippo to relay news of the forest's existence and presumably his well-being to Fluff. This shows an enduring connection persists between the siblings despite their separation.