The Mare Rings are Rings, along with the Arcobaleno Pacifiers and the Vongola Rings, that make up the Tri-Ni-Set (7³), three sets of extremely powerful Rings that are said to have created the world. At the end of the Future Arc, the Mare Rings were sealed in the past by the Arcobaleno. The Mare Rings have their own ability, like the Pacifiers and the Vongola Rings.