This is stylization of the world-famous carving "Sigurd the Slayer of Fáfnir" on portal plank from Hylestad stave church.
Also these events are described in epic poem The Nibelungenlied.
more info https://en.wikipedia.org/wiki/Fafnir             https://en.wikipedia.org/wiki/Sigurd

Metal: sterling silver (925)
Weight: approx. 10 g (0,35 oz)

The gods Odin, Loki and Henir arrive at the waterfall, and Loki kills the otter. They are then left with Hreidmar, who recognizes in the animal his own son Atra, who liked to fish in the form of an otter. With the help of his sons Fafnir and Regin, he takes the three gods captive. As compensation for the death of his son, he demands an amount of gold that could fill and completely cover the otter's skin. Loki sets out to retrieve this treasure, and he takes the dwarf Andvari's fortune, including the ring that the latter would like to keep for himself. The dwarf then curses his treasure so that it brings death to anyone who possesses it. The gods give the gold to Hreidmar, and Loki repeats Andvari's curse to him. Fafnir and Regin take some of the treasure from their father. Since the latter does not want to give it to them, they kill him. Fafnir then refuses to give half of the gold to his brother and, threatening him, forces him to flee. As for him, he goes to Gnithaheid, where he takes the form of a serpent and lies down on his gold to keep it.

Regin has established himself as the master smith of the Danish king and was responsible for raising Sigurd. He several times persuaded him to seize Fafnir's gold. For this purpose he forges for him the sword Gram. Fafnir's murder is described in detail in the eddic poem Fáfnismál, the saga of the Völsungs and quickly in Skáldskaparmál. Following Regin's advice, Sigurd digs a hole where he could hide, on the path that Fafnir usually chooses to get to the water point. In the saga Völsunga indicates that an old man then appears, who is none other than the god Odin, who advises Sigurd to dig other pits, which will allow the blood of the monster to be collected. This done, the serpent arrives rumbling and spewing fire, and when it crawls over the pit, the hero pierces it with his sword. Hence Sigurd's nickname, Fafnisbani, "the murderer of Fafnir." Before he dies, Fafnir reveals to Sigurd the curse associated with the gold and warns Sigurd against Regin. Regin then asks Sigurd to prepare the heart of the monster for him. As he cooks, Sigurd puts his finger to his mouth and tastes Fafnir's blood. From this moment he understands the language of the birds and thus learns that Regin intends to get rid of him in order to take the gold. So Sigurd decapitates Regin, eats Fafnir's heart and drinks their blood. Then he goes to Fafnir's lair and takes his treasure.

Siegfried and Fafnir Viking Ring Mammen Style Norse Pagan Jewelry