Duergar

These are a malicious form of Dwarf  from Northern England.  They revel in tricking people into dying.

The dwarfs of the Norse, they live in the rocks and hills and are brilliant metallurgists, and are smiths for the gods. They were once the maggots in the giant Ymir's flesh, and became the duergar when he died. They became the partakers of human knowledge, and although they resemble man in most ways except for their short legs, long arms which almost reach the ground when they are upright, and grumpy dispositions, as well as the fact that they turn into stone when sunlight shines on them.