A Manacle is a type of interplanetary node that facilitates the flow of Mana between planets.
Manacles naturally occur as the result of an organized Saezerite crystal structure forming a connection with other structures with the same properties. These connections are maintained by the continual flow of Mana between them, which is facilitated by Eon energy. It is convenient to think of a Manacle as a seed, as not all Manacles will become fully functional in a short amount of time. The process may take several years, especially if the planet attempting to organize a Manacle structure does not contain an abundance of naturally-occurring Eon.
When first constructed, a man-made Manacle will be notably much weaker than a naturally-occurring Manacle. It will still allow connections to other, more powerful Manacles, but its retention of Mana will be lower, and its performance of sending Mana will be significantly worse. Often, the areas surrounding these artificial Manacles will be damaged drastically by Mana leaks, violent expulsion of Mana unfacilitated by Eon, etc. As a result of its connections to other Manacles, they will gradually build up a store of Eon energy, the amount of which depends on the connections. The addition of an Eon pool will significantly enhance the performance of a Manacle.
Manacles contain Eon in order to store Mana, and expel this Eon upon transporting the Mana to another location. Eon is expelled in two ways; first, the Manacle will attempt to transport Mana to another compatible Manacle. When one Manacle is transporting Mana to another, not all of its Eon will be expelled. If the recipient Manacle also contains a high density of Eon, the original Manacle will attempt to expel its Eon into the surrounding environment.
Effects-wise, Manacles tend to impose an environmental change on the areas in which they are erected, or otherwise naturally formed in. Primarily, Manacles are simply used as a vehicle for the transportation of Mana to other planets in the Manaverse. However, they also have a small degree of interaction with the Chains of Fate, manipulating subtly the area surrounding a Manacle to gradually repair damage to said area, often over the course of several centuries.
Manacles also have the secondary effect of awakening Domains, which in turn will occasionally trigger people to unlock the access to their Soul Phantasms.