A deity is a being made of magic power that is worshipped by lesser beings.
The deities of the Mortal Realms are not omniscient or omnipotent as they are dependant of their worshippers as their worshippers are dependent on them, both empowered by their relationship.
The deity receives power from acts of beliefs and proof of devotion by their faithful which means that the more souls that pay homage to the divinity or devote themselves to their creed the more powerful it becomes. This does not only provide raw power to the deities but the soul of a faithful also allows them to influence, perceive and even create some form of presence in the realms, with shrines and sites of worship having a similar, if weaker, effect.
In exchange a gods provides part of their power in their time of need, solving the various problem they might have. The very devout are especially attuned to the gods, allowing them to move power and work true miracles though them. The priests and the gods are bonded by spiritual energy that allows a god, in some cases quite literally, see through their eyes.
A deity can create a lesser manifestation of itself or a shard of their own godly might to observe events that are far from the reach of their physical manifestations. These manifestations are there and not there at the same time, coalesced from raw magic, invisible to everyone, except other divinities. In this form they are also able to summon enough raw magic to destroy things, like a Flux-Cairn. These forms take attention from their divinities and can be dispersed just as quickly.
Lesser manifestations can also be sensed by certain beings:
- Other Deities can sense the presence of other deities and often use these lesser manifestations to discuss and taunt each other.
- Tzaangors have magical senses that alert them that something is wrong in the presence of a gods lesser manifestation. 
- Sylvaneth Soul-Pods held hostage in the Hexwood can feel the presence of Sigmar and plead for rescue.
|Deities of the Mortal Realms|
|Incarnates||Alarielle - Gorkamorka - Grimnir - Grungni - Malerion - Nagash - Sigmar - Teclis - Tyrion|
|Zodiacal Godbeasts||Argentine - Auroxis - Behemat - Chimerac - Dracothion - Fangathrak - Gnorros - Hydragos - Ignax - Kharybtar - Lode-Griffon - Nyxtor - Ur-Phoenix - Vulcatrix - Vytrix - Ymnog|
|Chaos Gods||Great Horned Rat - Hashut - Khorne - Necoho - Nurgle - Slaanesh - Tzeentch|
|Underworld Deities||Brine-God - Stygxxian Goddess of Plenty - Vannah - Xereus|
|Other||Bad Moon - Gazul- Khaine - Kurnoth - Lunaghast - Mathlann - Myrmidia - Y'ulea|
- 1: Hammerhal & Other Stories, Dark God's Laugther
- 2: Age of Sigmar: Core Book (2nd Edition) - The Illumination of the Gods, pg. 111