Any Denizen above the Rank of Shade has one or more Attunements, corrisponding to the Substances used in their Transubstantiation. The most powerful and highly Ranked Denizens manage to achieve multiple Attunements. In many ways the Attunements chosen represent the "nature" of a Denizen, whether it be a Cherubim of Joy or a Demon of Fire and Instinct.
A Denizen is completely free in the substance it first attunes to, however there are some limitations to additional Attunements. Denizens who attune to a Material Substance, sometimes called Elementals, cannot attune to “opposing” elements- thus they may attune to Fire or Water and Earth or Air. Similarly, a Denizen generally may not be attuned to both Dark and Light Substances, there are no Denizens of Desire and Justice.
An exception to the rule regarding Dark and Light Substances occurrs in a case where a character has assumed two Attunements related to a single Domain and have no Attunements associated with any other domain. In this case the character can gain all three Attunements for that Domain through the normal process of Transubstantiation. There are legends that with sufficient Rank and the proper Powers a character can assume a final Attunement specific to their chosen Domain.
If the character is only attuned to Material Substances, and neither Light nor Dark, they are referred to as an Elemental.
A character attuned to Light Substances is called a Celestine. Unlike dark attunements Material-attuned Celestines generally do not add Elemental to this title.
Characters who have Dark, Light, and Material attunements are called Oracles and given great respect, but little trust.
If a Denizen attempts to damage another's Psyche for each Attunement that the target and attacker share the target receives a bonus to his defense draw. This bonus is equal to the shared number of attunements, squared.
Thus 1 shared Attunement grants +1, 2 grants +4, and 3 grants +9.
If the target shares all of the attacker’s Attunements the attack deals no damage, and as no character may possess no more than 4 Attunements, a pair of characters matching all 4 Attunements automatically deal no damage to one another, as would any character attacking another who shares all of their Attunements.
This is but one more reason Denizens fear combat with higher Ranked Denizens; Characters who might match their own Attunements; rendering the lower Ranking Denizen unable to do damage, and have still more Attunements; allowing the higher Ranked Denizen to attack, albeit with a penalty.
By some arcane provence of the Pact Fundemental Celestines treat all Light Substances as being the same for determining the Attunement defense bonus and whether the attacker can deal damage at all.
Each attunement is associated with a Domain, as appropriate to the Substance. For each Light or Dark Attunement a Denizen has that is associated with a given Domain they are granted an additional point in that Domain. If the character posesses an Elemental Attunement it grants two additional levels in the associated Domain. These increases do mean that a character might benefit from an increased rating in Domains they have not otherwise purchased, or that their Domain ratings might exceed those normally available to their Rank.
The Domains and the associated Attunements are;