The church grim is a guardian spirit in English and Scandinavian folklore that oversees the welfare of a particular Christian church and protects the churchyard from those who would profane and commit sacrilege against it.
The church grim usually takes the form of a large black dog and guards churchyards from those who would profane them including thieves, vandals, witches, warlocks, and the Devil himself.
In the 19th century, folklorists believed that it had once been the custom to bury a dog alive under the cornerstone of a church as a foundation sacrifice so that its ghost might serve as a guardian.
Like many spectral black dogs, the grim, according to Yorkshire tradition, is also an ominous portent and is known to toll the church bell at midnight before a death takes place.
During funerals the presiding clergyman may see the grim-looking out from the churchtower and determine from its aspect whether the soul of the deceased is destined for Heaven or Hell. The grim inhabits the churchyard day and night and is associated with dark stormy weather.
When a new churchyard was opened it was believed that the first person buried there had to guard it against the Devil. In order to prevent a human soul from having to perform such a duty a black dog was buried in the north part of the churchyard as a substitute.
According to a related belief in Scotland the spirit of the person most recently buried in a churchyard had to protect it until the next funeral provided a new guardian to replace him or her. This churchyard vigil was known as the faire chlaidh or “graveyard watch”.
A black dog is normally the size of a calf, with a shaggy black coat and glowing,sometimes fiery eyes. They are always solitary. Wandering black dogs may be encountered in almost any church area, normally at night.
The dog is usually encountered by a lone traveler or, at the most, a group of two or three. It is heading in the opposite direction to the traveler(s) and is content to ignore and be ignored.
However, if anyone tries to strike it or take any other evil action, the dog will use supernatural power to strike the offender blind, dumb, mad or worse.
It can do this simply by stopping and fixing the victim with its fiery eyes, although it does not even need to do this; the effect seems to be spell-like rather than a gaze weapon.