Izumi is Micchan's adopted nephew, who he helped raise from the time he was small, after Izumi's mom died, and then as well after his dad died. Izumi always was possessive of Micchan's attention, even when he was young.

Izumi grew up and went to college and then eventually, at 20, he moves back home with Micchan. He surprise kisses Micchan and tells him he came home to become Micchan's lover!?

Despite his kiss attack, however, Izumi is respectful of Micchan's feelings of surprise and hesitation to enter into a relationship with a child he helped raise, who has now become a young man. They both try to be respectful of each other's feelings as they navigate their new dynamic and Micchan struggles with coming to terms with the new way he is coming to see Izumi.