Sin Eater

I have heard of this in Celtic Mythology, there was a book about it, and a Movie.

"In Celtic mythology, one man from a community was chosen by lot to become an outcast, the Sin Eater.
This person agreed to live as a hermit until summoned by a bell when a community member had died. The Sin Eater would then stand over the grave and suck in or “eat” the sins of the dead person so that he or she could pass safely into eternity. The Sin Eater was not allowed to participate in life with other human beings. He wore robes with a deep hood that protected the populace from seeing him, and at the times he was called upon to perform his duty, all backs were turned to him and he was not looked upon at all.
When his sin eating was done, he crept quietly and quickly back into the woods, disappearing until he should be needed again. In his vocation, the Sin Eater was like a Christ figure.
This culture, knowing nothing of Jesus Christ’s sacrifice for the sins of all people, had perceived the deep need for mankind to be forgiven and redeemed for the wrong things done in life, and had built a system of redemption and salvation centered on human effort."

HOWEVER, it is not only in Mythology.

There are accounts of this custom in villages in Wales, near the border with England in the County of Hereford. Here is one account, written in 1822:

"Sin eaters and the custom of sin eating seem to come from Wales. Early descriptions of the ritual all mention the bread eaten over the corpse, as well as the payment of sixpence to the person assuming the sins of the dead.
In the county of Hereford was an old custom at funerals to hire poor people, who were to take upon them all the sins of the party deceased, and were called sin-eaters.
One of them, I remember, lived in a cottage on Ross high-way. The manner was thus: when the corpse was brought out of the house, and laid on the bier, a loaf of bread was delivered to the sin-eater over the corpse, as also a mazar-bowl (made of maple) full of beer, which he was to drink up, and sixpence in money; in consequence whereof, he took upon him, ipso facto, all the sins of the defunct, and freed him or her from walking after they were dead.
In North Wales, the sin-eaters are frequently made use of; but there, instead of a bowl of beer, they have a bowl of milk. This custom was by some people observed, even in the strictest time of the Presbyterian government.
And at Dyndar, volens nolens* the parson of the parish, the relations of a woman deceased there had this ceremony punctually performed according to her will. The like was done in the city of Hereford in those times, where a woman kept many years before her death, a mazar bowl for the sin-eater, and in other places in this county, as also at Brecon, at Llangore, where Mr. Gwin, the minister, about 1640, could not hinder this superstition."

*volens nolens - is a legal term meaning "willing or unwilling", and in this context means "whether the parson of the Parish gave his consent or not."