The Bubble Love of the Mermaid Vol 1 manga

Description:

With her apprentice Yuicia and the little cat-sith Kuro gone, Chise resumes her daily life in the Wasteland of Nothingness alongside her trusty companion Teto and their twenty-odd attendant dolls. Over the years, what used to be a desolate, barren land has turned into a beautiful, lush forest and the new tenants from the floating island have left it busier than ever, to Chise’s delight. But these changes soon catch the attention of the nations next door, and it isn’t long before they start making “housewarming visits.” Unable to live in hiding any longer, Chise has to do the one thing she’s been dreading the most: open the wasteland to the rest of the world.