Hana Kappa is the main protagonist of his namesake anime, a young kappa boy who lives in the verdant village of Yamabiko. His most defining physical trait is the flower that blooms from the top of his head, a unique feature that can change its shape and color to mirror his emotions or the environment around him, serving as a visible gauge of his inner state. This characteristic is central to his identity, as his name itself combines hana, meaning flower, with kappa, the mythical Japanese river creature he is.

Hana Kappa is part of a close-knit, multi-generational family, living with his father, mother, grandfather, and grandmother. His background is steeped in the traditional bonds and shared values of his community, where he interacts with other kappa and anthropomorphic friends, most notably the steadfast Chōbei, the inventive Garizō, and the spirited Ageru-chan. His personality is a blend of inquisitiveness and resolute determination. He is generally portrayed as curious and adventurous, often approaching new situations with an energetic and sometimes impetuous nature, but this is balanced by a strong protective instinct that drives him to shield others from harm. His central motivations are rooted in devotion to his family, loyalty to his friends, and a deep commitment to the well-being of his community.

Within the story's narrative, Hana Kappa frequently finds himself as the driving force behind major quests and adventures. One of the most pivotal storylines involves a daunting mission to rescue mothers who have been abducted from his village, a journey that pushes him to lead his friends through perilous extremes such as frozen mountains and scorching deserts. In these challenges, his role evolves from a curious boy into a strategic leader, marshaling his peers to overcome physical and emotional hurdles through collaboration, ingenuity, and trust. This highlights a key aspect of his development: his capacity for resilience and his ability to inspire communal unity in the face of adversity. His key relationships, particularly with his family and close circle of friends, are the foundation of his support system and are central to the stories, as their shared adventures and unwavering support for one another are a recurring theme.

While his core physical traits and mannerisms remain consistent, his emotional growth is often symbolized by his ever-changing flower, which acts as a persistent emblem of his evolving feelings and the external challenges he faces. His notable abilities are not rooted in superhuman power but in his cleverness, his courage, and his ability to bring out the best in those around him. His determination and hard work are also recognized as qualities that can rejuvenate and bring positive change to his surroundings, contributing to the academic and communal culture of his world. Through a mix of whimsical adventures and heartfelt trials, Hana Kappa embodies values of friendship, family, and respect for nature.