Uruoi-chan is a central figure in the Shizuku Forest community, originally depicted as a skin lotion sprite, though some manga volumes present her as a pink lemonade droplet sprite. Her name translates directly to "moisture" in Japanese, reflecting her liquid theme.

She resides with her family in the Department Store of Shizuku Forest, operating alongside her older sisters, Shampoo and Rinse, who are shampoo and rinse sprites respectively. Uruoi-chan embodies a distinctly feminine and fashionable personality, drawn to stylish and aesthetically pleasing items. Her physical form is a pink droplet, featuring a tilted red ribbon on her forehead, yellow wings, and three upward-pointing eyelashes on each eye.

Her most significant relationship is a deep, persistent romantic affection for the protagonist, Shizuku-chan. This bond proves pivotal when Shizuku-chan becomes trapped in ice; Uruoi-chan's genuine feelings enable her to thaw him with a kiss, demonstrating their unique emotional connection. Beyond this central romance, she is prone to developing crushes on other male forest sprites.

Socially, Uruoi-chan maintains close friendships within Shizuku Forest. She acts as a caretaker and companion to Mirumiru, a young milk sprite, and shares a rapport with the snail character Tsumurin, often finding common ground. Despite her sociable nature, she possesses a notable lack of musical ability, described as tone-deaf, and her singing frequently causes discomfort among others.

In the human-reimagined spin-off manga "NiJiRo Fairy Shizuku-chan," Uruoi-chan appears with pink hair and wears a one-piece dress, while her core personality traits and relationships remain consistent. Official media provides no information regarding significant character development or alterations to her background story beyond these established traits and relationships.