Binding magic is presented in Wizards of the Coast’s Tome of Magic. Necessary adaptations are outlined here. For more details, see the book.

The magic of binding is as old as language, predating all other forms of magic. While it has been largely eclipsed by other arcana, binders remain scattered across the Wilderlands, and some still research binding sigils for new spirits to invoke [inventing new bindings is akin to researching personal truenames (see Truespeak), but each power functions as a separate name]. Unlike conventional spellcasters, binders need no special lineage nor innate talent. Anyone can learn the binding arts, and anyone with sufficient strength of will has a chance to excel at it. Many who learn of pact magic, however, shy away from it. While it is a quick path to impressive power, they balk at submitting their souls to such intimate congress with spirits — especially the alien beings that most binders consort with. Spirits often respond to the calls out of hunger, both for sensation and for the living essence they glean from the pact (one point of essence for each successful pact per day). In fact, this essence is all that keeps some hoary spirits going, long after their mortal descendants (and civilizations) have been lost to the tides of time.

To form a pact, a binder must learn an entity’s sigil and enough information about it to phrase a summons (truename research helps greatly here). Also, the binder must have sufficient power (class level) to forge the pact. Each binder is more familiar with summoning certain entities, equivalent to a caster’s known and recallable spell lists. The binder may stumble across new bindings in tomes or learn them from other binders, or may research new bindings for known entities. A binder may add an entity to its list of recallable bindings after such research, but may only adjust the list of known bindings upon reaching a new level. Recallable bindings must be performed from a text or other record, or with the help of a binder more familiar with the entity. They take twice as long to perform as a regular binding.

Technically, all beings have sigils and binding rites, but these must be discovered through scrupulous research or revealed through divine insight. Mortals can learn binding rituals for themselves and their peers, but binding rituals on a living mortal automatically fail – the bond between soul and body is too strong. Most outsiders would be susceptible to binding rituals, but they are not prominent enough to attract a binder’s attention, nor desperate enough to seek it out. Several kinds of outsiders make up the vast majority of known binding sigils:

• Vestiges: Far and away the most commonly distributed sigils belong to vestiges, the remains of failed and destroyed gods. They are hungry for even the meager scraps of existence (and essence) that binders provide, and they are small enough to remain within reach of a mortal binder’s call.
• Deceased: After death, some strong-willed souls carry on as Deceased. These often torment the living as ghosts and other spectral terrors, but some develop enough of a reputation to come to a binder’s attention. They are more powerful than most vestiges, but generally require more research to fully develop the power of their binding. They enter into pacts for the essence, and to influence the living world.
• Animae: Animae straddle the space between outsider (or Deceased) and god. Instead of engaging in planar politics like most of their kind, they tie themselves to the material plane for essence. This makes them more accessible than other outsiders, more powerful than vestiges or the Deceased, but still within a skilled binder’s reach. They enter into pacts to spread their influence, protect their charges, and perhaps ascend to divinity.
• Divine beings: Deities hover on the edge of what a mortal binder can properly contact. Fledgling deities, however, will often take any advantage they can get, and a binder can be almost as useful as a priest, and far easier to attract.
  • Servitors and avatars of of deities: When a god becomes too potent to answer a binder’s call, they may carve off a piece of themselves that is still small enough to call. This is difficult and expensive, but does not require a new sigil. A god may instead share the sigils of its servitors (outsiders that flock to it as their Anchor). These count as new sigils, but the god does the research on the binder’s behalf.
  • Quasi-deities: Those beings who have reached Divine Rank 0 lack the power of a true god, but they are still potent beings in their own right. They are fully capable of using the binding sigil to carry on conversation, and cannot be compelled to the pact. This makes binders hesitant to deal with quasi-deities unless they have an existing relationship.
  • Lesser deities: Having delved the depths of the cosmos and claimed a divine portfolio, some lesser deities are still within a binder’s reach. They grant better and more frequent powers than their lesser peers, but they become harder to bind, and more fickle in their service, as they grow in power.

Animae, Anchors, deities, quasi-deities, the deceased, and vestiges (failed or destroyed gods) all have sigils that make them accessible to binders and other practitioners of pact magic. Most animae and deceased are rarely bound, since they are unlikely to come to mortal attention regularly enough to catch a binder’s eye. Similarly, most deities exceed the scope of all but the most powerful binders. Binders typically deal only with vestiges, since they are timeless, and are so eager for contact with the material world that they put up little fight.

The deceased rarely leave sufficient mark on the mortal world or the Shadow to catch a binder’s attention. Those that do enter into pacts find that an active pact provides some protection from dissolution, in addition to a modicum of essence. While they grant powers like vestiges do, the deceased (or their binders) must spend time in research to unlock the binding powers, which can take months for even a skilled binder. Many powerful beings research their sigils while they still walk the planes. While the sigils have no effect until their destruction, it becomes easier for their followers or later adventurers to invoke them. Some undead even establish cults of binders to this specific end. Access to this research grants a +10 insight bonus to research rolls to discover the sigil and unlock its powers. Deceased typically have a vestige level of 1/4 their CR (rounded up), and their DC is the “take 10” value for the highest of Bluff, Diplomacy, and Intimidation.

Animae may place a taboo on anyone establishing a pact with them, preventing them from divulging information about the anima and from damaging or despoiling the people and places important to it. Failure to observe the taboo will break the pact, give the anima the right to decline further summons and dealings, and give the binder a -10 penalty to its next three bindings with the anima, should it choose to respond. Animae typically have a vestige level of 1/3 their CR (rounded up), and their DC varies according to the distance from their sphere of influence.

Any being that functions as an Anchor has established enough of a cosmic presence for binding purposes. No few binders learned their art from the lurid whispers of imps and quasits, imparting the lore to enter into pacts with their masters. Other Anchors (or their subjects) share these secrets far more rarely. Anchors can be bound like animae, and their DC is the “take 10” value for the highest of Bluff, Diplomacy, and Intimidation.

Quasi-deities (divine rank 0) may answer summons and enter into pacts, and many do so to help establish their earthly cults and expand their influence. Even after a successful summons, the deity may decline to form a pact, and will often do so if the binder’s alignment opposes theirs. Quasi-deities may break a pact immediately if their host directly violates their ethics or philosophy, and the binder suffers a -10 penalty to its next binding to that deity. Quasi-deities make up for these impositions by offering powers that can be used again in 1d6 rounds, rather than the normal 5 rounds for vestige powers. Their minds are also more intact than those of vestiges, and the summons and binding are more likely to involve real dialog and information. Their vestige level is 1/3 their ECL, and their binding DC is typically around 25 (or calculate DC per binding the deceased).

Gods (divine rank 1 or more) are theoretically just as available as quasi-deities, and sigils for several are widely known. The power necessary to summon a fragment in a circle, and the difficulty in binding the summoned divine mote, generally puts gods well beyond the power range of even groups of high-level binders. As a god advances in power, the special requirements of the summons become more onerous, and any being with divine rank 1 or more need not respond to the summons at all. The vestige level of a divine being is typically 4 + its divine rank, and the DC for the binding check is 25 + (divine rank x 5). The powers granted by gods, however, are even more potent than those of their lesser brethren. Not only can they be used again in 1d6 rounds, but they last one round per divine rank. Gods can count binders who know their sigil as anointed priests, and any binder with a pact with the god counts as a free location for the god’s remote viewing power. Some gods use binders to build a quick power base in the mortal world, despite the inherent risks in disseminating their sigils. As they grow beyond the reach of mortal summons, they typically guide their cults toward other character classes. If a god’s vestige level rises out of mortal reach, the god may opt to continue existing relationships at the previous level, but all new relationships operate at the new level. Thus a god becomes more difficult for new binders to summon as it gains power, but older servants are not turned away.

Gods that outgrow their binder cults may distribute sigils for their servitors, or develop avatars small enough for binding. In either case, these function as new sigils that binders must learn, but the god typically provides all the necessary information through direct intervention.