Fushisha to Assassin no Death Game Seisaku Katsudo (Volume)

is the first volume of the Fushisha to Assassin no Death Game Seisaku Katsudo light novel series, written by Kaede Asamiya and Illustrated by Shigure Ui. It was released under the Dengeki Bunko Imprint in July 2018.

Synopsis
Ikuto Womiya is an ordinary high school student with an immortal body who repeatedly resets his death in return for the "contract" he signed three years ago. After school as usual, the child suddenly appeared. "I'm Reona Ayamusaki. Will you die for me?" The girl, who lost her parents early and became the head of a young but assassinated clan, is suffering from a murderous urge that interferes with her daily life due to the "curse" that has continued since her ancestors' generation. It seems that he asked Ikuto to do it-- !? A forbidden romantic comedy where two people who follow a strange fate by "contract" are killed and killed each other!

(source: Amazon JP - Translated)