Kimi to Kazoku ni Naru made

is a japanese manga series written by Shimotsuki Kinusa. It began serialisation in the September 2020 issue of Manga Time Kirara Forward.

The series is currently released under 2 volumes from March 2021. (as of December 2021)

Synopsis
Minoru, a high school student who is in love with Chisato, a female college student who rides on the same train every Friday. Her feelings never stop and he even confesses to her, but she was the daughter of her father's remarriage partner ...! The first volume of a warm romantic comedy, woven by two people who unexpectedly became a family as "sister-in-law", is finally here!

(Source: Bookwalker JP - Translated)