The Long Night

There was a time when the twin gods of death, Morigawa and Natsugawa, were engaged in a fierce battle with the goddess of darkness and loss, Hamamoto. The twin gods were so preoccupied with the fight that neither were able to attend to their usual duties. Without Morigawa to claim the dead, their spirits lingered and haunted the lands. Without Natsugawa to maintain order in the afterlife, undead began flowing back into the mortal realm. This period of time escalated over the course of three moons, during which time Seinnaris was plunged into chaos.
The Long Night was finally ended when the three deities reached an agreement and returned to their duties again. Hamamoto gifted Mercy and Closure to the twin gods, who in exchange agreed to facilitate her annual day of Darkness.