He was the son of HREIDMAR the wizard, together with two brothers, OTR and REGIN. Shape-changers all. When OTR was in otter form, LOKI, who fancied a nice bit of otter to go with his fish, killed him by mistake.
This was a big mistake since he turned up at HREIDMAR’s house in the company of HONIR and ODIN bearing a strangely familiar otter skin. The wizard family thought LOKI was a rotter. Now LOKI, HONIR and ODIN were in deep trouble.
LOKI, using all his considerable cunning, suggested a hefty ransom fee to repay his debt. This was agreed and the other two Gods were taken hostage until his return. Knowing where ANDVARI the Dwarf King kept his treasure, LOKI forced the dwarf to hand it all over, even down to a special gold ring he’d just forged. ANDVARI just had time to curse the ring so it would bring doom to whoever owned it.
LOKI never got to own it — in fear of his life and those of his compatriots he took it straight to the wizards, who released the Gods after a quick gloat.
FAFNIR gloated the most. He was so inflamed with greed he turned himself into a dragon and stole the hoard, hiding it in a mountain lair where he could carry on gloating. He killed his father and exiled his brother REGIN, who by chance ran into the hero SIGURD.
If you see this ring, don’t faff or futz around — get in touch with ANDVARI and ask about the reward money.