Hiroshi Nakaizumi is a supporting character in the anime Lagrange: The Flower of Rin-ne. He is the uncle of the series' protagonist, Madoka Kyono, and is recognized as the owner and operator of a combined surf shop and restaurant named Be With Hiroshi, often abbreviated as BWH. His establishment serves as a central gathering place in the coastal city of Kamogawa, where much of the story takes place.

At 44 years old, Hiroshi is an adult presence in the lives of the younger characters, providing a stable and welcoming environment. His daughter, Youko Nakaizumi, is a recurring character who is closely involved with the military organization Novumundus and often worries about Madoka's safety. Hiroshi’s primary role in the narrative is tied to his business, which functions as a hub for the series’ characters. He offers part-time employment to several of the main heroines, including Lan and Muginami, whose contrasting personalities and work styles attract many customers to the restaurant. Later in the series, his shop continues to be a focal point, even serving other characters such as Kirius, Izo, and Array in various capacities.

Specific details regarding his personality, personal motivations, character development, or notable abilities are not extensively detailed in available information. His significance is derived from his familial connection to Madoka and his role as a local business owner whose establishment provides a consistent and homely backdrop for character interactions and moments of respite from the series' central conflicts involving Vox pilots and interstellar war. He is firmly positioned as a secondary or supporting character, primarily appearing in scenes set within the day-to-day life of Kamogawa rather than in the high-stakes mecha battles at the offshore base, Pharos.