Band of Fenrir

Following the death of the notorious werewolf Fenrir Greyback decades prior during the Battle of Hogwarts, his surviving, deeply embittered followers sought a way to preserve his legacy of weaponized lycanthropy. Without their alpha, and heavily hunted by Ministry of Magic Aurors, a rogue cell of Dark Artificers successfully bypasses the natural law of the curse after decades of experimentation and created the Band of Fenrir. Instead of relying on a physical bite during a full moon, this silver-and-pewter band acts as a synthetic vector for the Homonculus Lupus blood curse. It is designed to look like a harmless ring, only to forcibly infect whoever is unfortunate enough to put it on.

The inner lining of the band is enchanted with microscopic silver barbs. The second the ring is slipped onto a finger, the barbs pierce the skin to draw blood, completing an artificial "blood-to-blood" transmission. Within 24 hours, the curse binds permanently to the victim's magical core. Because the ring is forged from an alloy containing silver—the absolute bane of werewolves—the item induces a horrific, localized magical rejection. Once infected, the wearer cannot pull the ring off their finger due to a Sticking Charm tied to the curse. When the full moon rises, the silver burns fiercely into the flesh, making the wearer's physical transformation significantly more violent, chaotic, and painful than a standard werewolf bite.

The Department of Magical Law Enforcement classifies this as a Class A Cursed Object. Dark magic detectors fail to pick up its malicious nature because the creators masked it with a false aura, making it register to basic detection charms as a harmless Ring of Animal Friendship.