|Natural Magic, Caster, Caster link, Juice, Scroll, Magic Item, Spell, Grandiocosmic Strings, Nodes|
 Proposed Canon
A Caster link is made when two or three Casters are joined physically (via holding hands or by a chain, for instance) and mentally through a Thinkamancer in order to create a whole greater than the sum of its parts. The linked Casters can perform Spells far more powerful and complex than any single Caster could consider possible. Casters united in this way are said to be linked.
A Thinkamancer joins with one or two other Casters to create a combined consciousness. The process of creating the link can be aided by each Caster recalling how it felt when it first cast a Spell of its Discipline, which is described as warm, comforting, and familiar.Erf-b1-p135 The casters then lose their individuality and revert to representing only their Discipline. It is still possible for a Caster to remember its former existenceErf-b1-p046, but using this knowledge strains and might break the link.Erf-b1-p054 The link is fragile, and can be broken by merely calling one of the Casters by its name, so the linked Casters are referred to by their Disciplines instead (ie. Thinkamancer, Dirtamancer, Lookamancer, etc.).
Breaking the link can result in damage to the minds of the Casters, but this is similar to the backlash of other Thinkamancy Spells, so a good Thinkamancer can protect herself (or himself) from the damage by forcing the other Casters to bear the brunt.Erf-b1-p084. Such backlash can lead to severe trauma, including temporary catatonia, insanity, or death. Erf-b1-p077
A two Caster link may be dissolved by the Thinkamancer that began the link without harming either Caster. A three Caster link cannot be safely broken without the help of other Thinkamancers.
 See Also
To discuss the power of speculative link-ups, please visit Speculative Link-ups.
Since the Arkendish can provide unmatched Thinkamancy to a caster of a different discipline, effectively making 1 caster count as 2, it might be possible to use the Arkendish for a 4 discipline linkup. It is notable that Charlie and Olive performed caster links intended to learn how to emulate other disciplines with Flower Power, including disciplines other than Thinkamancy and Carnymancy.
It is rare, but possible, for a single caster to become master-class in more than one discipline. Isaac for example, is a master of Thinkamancy and Lookamancy, and an adept at Foolamancy. It might be possible for such a caster to perform feats similar to caster links. Maybe even add their extra disciplines to an actual caster link, resulting in a linkup with more than 3 disciplines involved. It should be noted though, that in a caster link, the casters effectively become avatars of their own disciplines. So while it might be possible for them to simulate other disciplines using their own natural discipline (like how Olive Branch created Flower Power that produced the effects of Healomancy), they might find it difficult to access their other disciplines directly.