Doukyuusei Seikatsu

Synopsis

Mizuno and Mitazono were middle school classmates with polar opposite personalities. One day, years later, Mitazono calls Mizuno up to help take care of some stray kittens. Mizuno agrees to stay in his house to look after the kittens for a short while. This is living together with a classmate! (Source: Shinshokan, translated)