From Summer Rain:

Akamatsu Taichi aims to be a shoujo mangaka. Despite being the heir to a large enterprise, he moves out and begins to live alone in a run-down apartment. One day, Taichi was asked for help by a girl who lives in the next room - a girl named "Midori". A scramble of friendship and love - a sweet romantic comedy!

Yukimi is her real name but everyone calls her Bambi. She is the student discipline committee member who locks students out of the school if they're a minute late but herself sneaks cigarette breaks on the roof. Lone wolf (Dhole, Asiatic wild dog) transfer student Tetsu (everyone pronounces it Tooru) Nagasawa who hops the fence after she locks it and breaks her cigarette in half when he finds her on the roof, yet he is a super nice guy to a mother and baby on the train. Bambi already has a boyfriend but will the wolf steal her heart?

“‘I’ve got someone I love more now. Goodbye’ was written on the note left behind when she disappeared. It’s just me and the cat now.” Yūsei dreams of succeeding as a graphic designer, but he spends his days without being able to make a difference while living in a town near the ocean. His girlfriend, Akane, left him, and he sank to rock bottom, but his cat started to unexpectedly expand his world…

(Source: LemonadeScans)

Included One-shot:
Volume 1-2: Kazoku Zenya