Fáfnir
In Germanic heroic legend and folklore, Fáfnir was a dwarf or other type of humanoid who had shifted into the hamr of a Germanic dragon (a worm, "serpent", in period nomenclature) in order to protect a treasure, eventually being slain by a member of the Völsung family, typically Sigurð. In Nordic mythology, he is the son of Hreiðmarr, as well as brother of Regin and Ótr.