Dark Horse describes Cat + Crazy:
High schooler Kensuke Fuji adores cats, but in a family full of people who are allergic, he's never been able to spend much time with the furry felines. When he meets the Ultimate Cat Whisperer, Kensuke finds a kindred spirit who seems to understand everything about cats! Deciding to become a disciple of this “kitty bonkers” cat-guru, Kensuke is on his way to learning the secrets of the Cat Fist Way, as a doorway into the secret world of cats opens up!
Translator Davisson said, "Cat + Crazy is catnip in manga form. Sweet, zany, and keeps you on your toes with the story never quite being what you think it will be."
Nadatani launched Cat + Crazy in Shogakukan's Shōnen Sunday S magazine in October 2015, and ended it in February 2018. Shogakukan published the manga's sixth and final compiled book volume in April 2018.
Nadatani launched the Cat + Gamer (Neko Gurashi no Gamer-san) manga in Shōnen Sunday S in November 2018, and ended it in January 2022. Shogakukan published the manga's eighth and final volume in April 2022. Dark Horse is releasing the manga in English, and shipped the sixth volume on October 29.
Source: Press release