Tomoe Yukihira, father of Itsuka and husband of Shinri, is an adult male with brown hair and brown eyes. His name signifies "huge comma design," while his surname Yukihira blends "snow" with meanings like "flat," "broad," "level," "even," and "peaceful."

During high school, Tomoe played guitar. His performance at a school fair inspired classmate Nagomu Irino to pursue music. Their friendship deepened at Fuku Fuku Cafe, where Tomoe worked part-time after moving out in his second year. He left for Tokyo after graduation, severing contact despite Nagomu later searching for him there [citation:].

In Tokyo, Tomoe met Shinri and they had Itsuka. With Shinri often occupied by work, Tomoe primarily raised their daughter, shouldering near-single parenthood. Ultimately, he left Itsuka at Nagomu's family confectionery, Ryokushō, to shield her from his own violently abusive father, who had threatened to kill both Itsuka and Shinri. To ensure Itsuka stayed safely with her grandfather, Tomoe made her believe he didn't want her, accepting her potential hatred as the price of her protection.

Tomoe endured lifelong severe physical and emotional abuse, resulting in significant PTSD and emotional scars that shaped his family circumstances. His fears proved valid when his father stalked Itsuka due to her achievements. After his father's hospitalization and imprisonment for these actions, Tomoe could gradually re-enter his daughter's life. He now participates in co-raising Itsuka alongside the Irino family, who provide her primary care at Ryokushō.