Mirumiru-chan, a spirited infant milk droplet sprite, calls the Milk Store in Shizuku Forest home. His name echoes the Japanese word for milk (*miruku*), embodying his pure essence. Though infantile in demeanor, he wields startling physical strength, effortlessly hoisting objects that challenge even fellow sprites. His bond with milk fuels an uncanny knack for tracing its source, often leading him to sip directly from grazing cows.

Communication flows solely through the playful vocalization "nyu," highlighting his early speech development. Raindrops trigger sudden growth spurts, occasionally swelling him beyond peers. His form mimics a glistening white milk droplet, adorned with wide, sparkling eyes, soft pink blush marks, and translucent light-blue wings. A pale blue bib, embroidered with "MILK" in matching hues, remains his constant accessory.

He thrives alongside companions Shizuku-chan, Uruoi-chan, and Tsumurin, diving eagerly into their adventures. Though his friendship with Yodare, a slobber sprite, sometimes raises eyebrows, his cheerful innocence and trusting nature anchor his infant-like charm, contrasting his mighty capabilities.

In the spin-off *NiJiRo Fairy Shizuku-chan*, where sprites take human form, he retains his toddler-like traits, clad in baby attire with his iconic "MILK" bib and persistent "nyu" expressions. This portrayal cements his role as the group’s eternally youthful, heartwarming presence, his core identity unwavering across all official narratives.