Nozomi Sakurai is a fifth-grade student and a main human character in the series. She is notably tall for her age and serves as the leader of a group called the Happy Hunter. Her appearance includes ash-blonde hair tied into a ponytail with small buns, and she has pink eyes. Nozomi made a contract with a Cocotama named Vivit, a small light teal mouse-like god born from her treasured locket pendant. Through this contract, she made a wish to grow up quickly. In addition to Vivit, she later forms contracts with several other Cocotamas, including Renge the paintbrush god, Pinco the purse goddess, and Nicolie the towel goddess.

Nozomi is characterized by a serious, strict, and mature demeanor. She is highly focused on her tasks and is considered reliable by those around her. She takes her responsibilities seriously, especially her role as a Happy Hunter, where she makes it a personal daily goal to help at least one person solve a problem. Despite her composed exterior, she shows signs of insecurity and shyness, and she can be hesitant when faced with decisions, even after making her contract. She tends to behave in a formal and conservative manner, often trying to maintain a stoic and composed image in front of others. Beneath this strict surface, she possesses a gentle and sincere desire to help others.

Nozomi had already met the protagonist Kokoro before transferring to the same school that Kokoro attends. In her interactions with other girls her age, she takes on an older-sister-like role, offering guidance and support due to her mature and responsible nature. Her key relationships include her partnership with Vivit, with whom she works closely to collect happy stars, and her friendship with Kokoro. Her development involves learning to balance her strict sense of duty with her underlying kindness, and she gradually becomes more comfortable expressing her genuine feelings. Her notable abilities include her leadership skills as the head of the Happy Hunter and her deep commitment to aiding others in her community.