Loki

Loki is a familiar name in mythology, and most know him as a trickster God. He had more qualities that just that though. He was associated with all forms of mischief, stealth, thievery, revenge, lies and dark magick, and natural disasters like earthquakes, and fires. Loki was a shape-changing Giant, married to Angerboda. They had three children. Two were considered monsters (Jormungand, the sea-serpent, and the Fenris wolf), and the third was Hel, the Goddess of the Dead.

After he tricked Hod (or Hoden) into firing the mistletoe arrow that killed Baldur, Loki was punished by being chained to a rock until Ragnarok. Not only was he chained to a rock, but a serpent hangs above him, dripping venom on Loki's face. As he writhes in pain, earthquakes are born.

During another one of his tricks, Loki had turned himself into a mare in order to lure a magick stallion away from its work on Asgard. From that encounter, Loki became pregnant and gave birth to the eight-legged horse, Sleipnir. Loki gave the horse to Odin.

One wonders why the other Gods tolerated such a trouble-maker in their midst. It's been suggested that Loki was originally a more benign character, but myths were re-written and altered with the coming of Christianity to make him fall more in line with the evil figure of Satan.