Dantoudai No Hanayome - Sekai Wo Horobosu Futsutsuka Na Tatsuki Desu Ga.

A “Dragon” appeared from the container that fell in front of Ryuunosuke Dazai–. The malevolently beautiful “Dragon”, Rinne Irako, was sentenced to death as a “Calamity” that could destroy the world and was being transported. However, whether it was a trick of fate, the “Dragon” girl had a miraculous encounter with the boy, and fate was about to change significantly. “It’s to save the world– come on, let’s love each other.”