The Ring of Hircine (also known as Hircine's Ring, or The Hircine Ring) is a Daedric artifact created by the Daedric Prince Hircine. In appearance, it is usually an engraved metallic ring showing the head of a wolf, although it has also been known to appear as a spiked leather buckler. The ring can temporarily give the gift of Lycanthropy to the wearer, and allows lycanthropes to control their transformations. Lycanthropes who possess the ring are not affected by the moons or by bloodlust, and can change form at will. Hircine punishes those that did not legitimately earn the ring, stripping the ring of its ability to control transformations and instead making transformations unpredictable. For non-lycanthropes, the ring is often useless, although it has been known to extend the wearer's life and allow for transformation into a werewolf. The ring is known to affect werewolves and wereboars, and likely works on other lycanthropes as well.
Tharsten Heart-Fang, a great leader of the Skaal of Solstheim, possessed the Ring of Hircine for many generations in secret, unnaturally extending his life and youth. However, in the events leading up to the Warp in the West, an agent of the Blades summoned Hircine through the Glenmoril Coven and was tasked with killing an ungrateful wereboar for the Prince. In return, a worshipper of Hircine gave the ring to the agent. By 3E 427, Tharsten was again in possession of the ring when he was captured by the Hounds of Hircine to act as Prey during the fulfillment of the Bloodmoon Prophecy. He was brought to the icy tunnels within the Mortrag Glacier, and took part in Hircine's Great Hunt. Tharsten encountered the Nerevarine during the Hunt, and used the ring to transform into a werewolf and attack. The Nerevarine defeated him and became the new owner of the ring.
Circa 4E 201, the Forgotten Hero along with an adventuring party ventured to Thornwell Farm near Riften chasing rumors of Barilzar's Mazed Band, having heard that the local farmer there was in possession of a magic ring. There, they fought off other treasure hunters and learned from the farmer that he lost the ring in the nearby forest. Within the forest, the party found a werewolf who attacked them. After defeating it, they learned it was the farmer's son. The farmer begged the Forgotten Hero to let him keep the ring, as it helps his son control his curse, but stories conflict on what was ultimately decided on. Some say that the Hero did a great deed and let the farmer keep the ring and thereby earned the favor of the wolves, while others say that the Hero took the ring and was cursed by the farmer, resulting in unpredictable transformations for whoever wore the ring.
The ring subsequently was found in the possession of a Nord werewolf named Sinding that same year, who stole the Ring of Hircine in an attempt to control his transformations. His plan backfired when Hircine cursed the ring, causing the wearer to transform at random and making it impossible to take off unless another willingly accepts it. Sinding was captured in Falkreath and thrown in jail for killing a little girl in his beast form. The Last Dragonborn visited Sinding in his jail cell, and accepted the ring from him, hoping to appease Hircine and have the curse removed. Sinding escaped from jail, and the Dragonborn hunted down a rare White Stag to earn the Prince's favor. Upon contacting Hircine, the Dragonborn learned that the Prince would not forgive Sinding's betrayal, and would conduct a Great Hunt where he would task hunters with killing and skinning him in return for the Savior's Hide. It is unknown if the Dragonborn joined the Hunt and lost the ring, saved Sinding from the hunters and had Hircine remove the curse, or betrayed Sinding by eliminating the hunters before turning on him and claiming both artifacts.