The One Ring

From the Comprehensive Rules 4.0:

This card type represents the uniquely powerful item that is the focus of the story of The Lord of the Rings. In the middle of the card, The One Ring has its subtitle. It has no twilight cost.

There are several versions of The One Ring, represented by different cards, but you’ll only use one version at a time.

See also building your deck, culture, kinds of cards, overwhelmed, Ring-bearer.