What's the name of that ghoul again?

Black and white ghost, also known as impermanence. In ancient superstitions, impermanence is regarded as the messenger of the soul after death. Impermanence is divided into black impermanence and white impermanence. Although black impermanence and white impermanence are ghosts, the former brings only disaster, while the latter brings fear and anxiety on the one hand and good luck to make a fortune on the other. This reflects a folk concept: ghosts have good and evil like people.

Keres (Keres)

In Greek mythology, when the God of Destiny determines the date of someone's death, the headhunter sends Keres to invite the dying person. Keres often floats on the battlefield, wearing a red robe with black skin underneath, their eyes flashing like wildfire, and their teeth are horribly white. When someone dies on the battlefield, Keres will let out a piercing scream, throw himself on the ground, suck blood from the wounds of the deceased, and then take it to the underworld.

There is also a corresponding goddess Valkyre in Nordic mythology. She is one of Odin's twelve maids, whose task is to lead the warriors who died in battle to heaven. The soul of the deceased was given a feast by God after his death, and he was happy every day.