Groth-Golka, the Demon Bird-God or the Bird-God of Balsagoð, is a monstrous bird-like fiend with sharp teeth, dwelling beneath Antarctica, vaguely resembling an extinct Pterosaur.
According to a passage, in the old times hosts of men came against him, but the beast was the greatest of all the devil-birds and he slew all who fought against him. It is also said that the priests, who were bewildered by his power, worshiped him as a god and thus was revered to as one. The priests then allowed Groth-Golka to inhabit one part of the Arctic Circle.
Any whom dare enter the Circle are very likely to meet their grizzly demise. Those whom have brought sacrifices to this fiend, are the only ones allowed to enter on the soil he claimed.