Kenryuu Tomosaka is the father of the protagonist, Kenji Tomosaka, and his sister Suzuka in the anime Lamune. He is a mature adult figure with gray eyes and black hair that reaches his neck, reflecting a typical design for a parental character in the series.

Kenryuu works as a judo instructor at the same school that his daughter Suzuka attends. In this professional capacity, he is depicted as being exceptionally strict, demanding complete discipline and effort from his students. This rigor is particularly pronounced when teaching his own daughter, as he does not accept any form of failure from her. This behavior establishes his personality as a serious and principled individual, one who places a high value on technique, perseverance, and success, without making exceptions for family ties.

In the narrative of Lamune, Kenryuu Tomosaka serves primarily as a supporting character whose presence helps define the home life and background of the main character, Kenji. His role as a father and instructor places him within the daily environment of the main cast, contributing to the story's grounded, slice-of-life atmosphere. His position as a judo teacher also links him to Suzuka, one of the supporting characters, reinforcing her personal discipline and the dynamics of her family life.

While the central focus of Lamune remains on the evolving relationship between Kenji and his childhood friend Nanami Konoe, Kenryuu represents the stabilizing presence of the older generation. The series does not extensively explore any personal development or changes in his character, as his function is largely to provide context for the younger characters' upbringing and current circumstances. There are no notable abilities attributed to him beyond his expertise as a judo instructor, which is his defining professional trait and a key facet of his identity within the story.