A Cat from Our World and the Forgotten Witch Vol. 1 by Hiro Kashiwaba

A sweet tale starring a gigantic cat who's summoned to a fantasy world by a lonely, elderly witch.

In her youth, Jeanne was a powerful witch who vanquished the evil Demon King and saved the world—but over time, the people she rescued have forgotten her. Now she is a lonely old woman living in a secluded forest...until she accidentally summons a cat from Earth to her home! The former city kitty is now gigantic and must acclimate to this new world. Can a cat from another world soothe the loneliness of the forgotten witch?