Meinya is a small mammalian creature classified as a Meinastilim, or "Child of Change," received by Prushka as a tenth birthday gift from Bondrewd. Prushka shortened the name from "Meinastilim" due to pronunciation difficulty. Srajo speculates Meinya resulted from Bondrewd's attempts to create an artificial Juusou, leaving the natural existence of Meinastilim unconfirmed.

Physically resembling a rabbit-sized being, Meinya has an oval-shaped body, stubby legs, and large feathered ears enabling short-distance flight. Its face features horizontally slit pupils, creating a toad-like appearance. Meinya possesses exceptional durability from pliant, flexible bones. When injured by a Narehate in Iruburu, its eye dislodged and intestines protruded, yet reversed easily during the village's Balancing phenomenon without permanent damage.

Meinya exhibits a vocal and affectionate personality, forming strong bonds with humans. It demonstrated deep attachment to Prushka, desperately lapping spilled contents from her cartridge after Bondrewd used it. Following Prushka's loss, Meinya joined Riko's group, accompanying them deeper into the Abyss. It signaled Riko upon Reg's return to Iruburu and was later seen alongside Maaa during pivotal moments, including Maaa's final embrace of Riko.

Functionally, Meinya's fur emits a scent allowing humans to temporarily perceive the Abyss's Force Field, known as "Fuzzy Stuff," aiding navigation without succumbing to the Curse. During sixth-layer travels, it detected a deceased Black Whistle delver, leading the group to critical artifacts. At Camp Number 5, Meinya eagerly perched on White Whistle Srajo's shoulder, indicating familiarity or recognition.

Trivia notes indicate Meinya shares a scent similarity with the author's parents' parrot.