Tenkuu no Shiro wo Moratta node Isekai de Tanoshiku Asobitai  

Tenkuu no Shiro o Moratta no de Isekai de Tanoshiku Asobitai, I Want To Play Happily Because I Got The Heavenly Castle, 天空の城をもらったので異世界で楽しく遊びたい, I wanted to play in another world because I received the castle in the sky

By chance, Daiki Shiihara's spirit was unintentionally gathered. In order to make amends for her error, the angel presented him with a present prior to sending him to another realm. Once there, he found that his deepest desire had been realized - a flying castle in a new world.