Series by 古味直志

Raku Ichijo, a high school student and heir to a yakuza family, dreams of a normal life despite his chaotic roots. His world flips when he’s forced into a fake relationship with Chitoge Kirisaki, a fiery transfer student and daughter of a rival gang leader, to keep the peace. Complicating matters, Raku holds onto a childhood promise and a mysterious key, searching for the girl he once vowed to marry.