The Ring of Pacts is the method by which the party learns summons from Final Fantasy XII: Revenant Wings. Using pieces of auracite, the player is able to unlock sections of the ring and form pacts with new Espers. By doing this, the player gains the ability to place them in an Esper Troupe and summon them from Summoning Gates. The Espers are organized on the ring according to their element (or non-element) and rank.
The ring is made up of many small nodes, each comprising one Esper. Each Esper costs an amount of auracite equal to its rank. Forming a pact with an Esper typically releases the nodes that are adjacent to it. Players initially start off from the inside of the ring, with the summons Alraune, Sylph, and Garchimacera already unlocked, and gradually make their way outward. Any Esper with which a pact can be formed glows yellow on the ring.
Rank I Espers are the weakest summons, and as a result they are plentiful and have a cheap cost of Affinity and cost 1 auracite. Rank II Espers are stronger than the Rank I Espers, so they cannot be summoned as often and have a higher cost of Affinity points and cost 2 auracite. Lastly, the Rank III summons are the strongest of all, so they require the most Affinity, cost 3 auracite and only one can be summoned throughout the course of a battle.
While Rank I and Rank II Espers can be immediately available in most battles, the Rank III Esper can only be summoned from a summoning gate; thus, they cannot participate in battles where no gates are available. Most Rank III summons must be defeated in battle before they can be unlocked on the Ring of Pacts. If one of these Espers has not been defeated in battle, a cracked stone will appear over its node in the Ring, blocking further progress.