Кітадзава Хаґумі

Hagumi is an energetic first-year student at Hanasakigawa Girls' High School and the bassist of Hello, Happy World!. She is in the same class as Kasumi. Outside of the band, she is friends with Saaya.

Hagumi is the only daughter of a family of butchers. They own a meat shop, where their bestselling item is their croquette. Her parents fight often and her father sometimes "disappears for three days because 'it felt so good'" and her mother tends to break things when she's mad. She also states that her parents don't allow her to be loud at home, which explains her energetic attitude outside. As such, she uses sports as an outlet. Hagumi also has an older brother, who taught her to play the guitar a bit in the past, which made learning to play the bass easier for her.

Lively and passionate for sports, Hagumi is known for her sunny disposition and energetic nature. She is cheery and can be a bit of a show-off, but she usually doesn't take things too far. She tries to convince others to indulge in her sporty hobbies at times. Despite her tomboyish personality, Hagumi has an affinity for cute things and has a complex over her boyish appearance. She especially loves Michelle's costume due to how it resembles a large stuffed bear. She can also be surprisingly sensitive and cautious of others' emotions as well.