Itoshi no Kunitama

Synopsis

After saying "I wanted to meet you for a very long time." Kunitama, a cat, jumped onto the chest of a university student, Makoto. However, the "destined person" that Kunitama have been searching for turns out to be Makoto's older brother, and to make things worse he's already married. Without further thought, Makoto proposed to Kunitama, who was weeping in sorrow?! "What about me?" "With true love, I could become a real human" (Source: Pixiv Comic, translated)