Series: Chen and Marisa and Mister (kamyo)

Mister wanted a Chen but since they're sold out got a Maricha instead. Maricha seems smart at first but got too spoiled and turned shithead.
Story unfinished and probably will never be. kamyo seems to no longer draw as this is his last work at pixiv. He's still active on twitter but doesn't post art there

Original title: ちぇんとまりさとお兄さん
Part 1: https://www.pixiv.net/en/artworks/81624622