The Spiritual Nexus (or simply, the Nexus) is a force of magical origin that metaphysically connects all spell casters, as well as being the source of their powers. They can draw power from the Nexus, or use it call on spirits of dead spell casters during certain rituals, which may be why while some spell casters use their powers, eerie whispers from an unseen force can be heard. Spirits of dead spell casters from a users coven can be used to guide said user and help them with rituals and their powers. Also, when using certain magic, such as telepathic communication from miles away, mental manipulation, interacting with spirits or raising the dead, the witches eyes tend to turn clear white, making the user look blind. Each kind of spell caster can feel others of their kind of spell caster, and can instantly identify spell casters through eye contact. As it was featured in the show, Bitten, only witches experience the Nexus's power and sense others of their race through it. As the Undoing commenced, witches could sense other witches weakening and dying. A standard power that was granted to spell casters was telekinesis, allowing a user to move objects with a thought, unlock and open doors with a wave of the users hand, making someone fly through the air and pin them to a surface, and cause the ground to explode as if a hand grenade or mine were in it. The user can also control physical forces such as pressure, allowing the user to choke someone telekinetically, cause them to bleed from almost every orafice, specifically the eyes, mouth and nose, or even to cause their body to experience pressure imbalance that could make them explode in blood and gore. Some dark spells allowed spell casters to cause someone to die of various causes from miles away, allowing Clara to execute people from her living room using something with the targets essence, such as a picture, hair, skin cells, blood, clothing, or jewelry, so long as they have touched it or it has been part of them. The more unnatural, immoral and evil forms of magic, or dark magic were more harmful, straining, and even lethal to the user, though mostly to those who were not experienced or well versed in using it. The worst of these seems to be magic that revives the dead or at least clinically dead, resulting in the agonizing death of the one who uses it. Objects, such as a talisman, Ruth's wooden ball, and Paige's looking glass were items that could respectively bestow and enhance power, as well as track the user, track certain individuals with the use of their targets essence, and allow the user to see and identify magic, especially dark magic, wherever it is cast. These objects were used in magic that spell casters seemed to be unable to without them. Aliester possessed candy that, once Savannah ate the red and he ate the blue, he could control her actions with the phrase, "I am the lock", to which Savannah would instinctually respond, "and I am the key. This may have been a form of potion, though it may have been alive, as a slug or insect like creature from the candy burrowed under the skin of Savannah's right arm. This control was enhanced by Savannah drinking Elena's blood under Aliester's control, making her his mindless slave. Dark users of magic could also use the Nexus to affect other spell casters, such as how Aliester caused Paige's voice to become demonically deep, to become hostile towards all werewolves, forget what was important, and physically and then telekinetically choke Elena when the latter tried reasoning with her. Ulster did this while the Undoing was weakening all witches bound to the Nexus. Spell casters can also go to certain places where others of their kind are buried or where they can draw strength from others in their coven, all in order to harness power and perform greater magic. Spell casters can draw strength from others of their kind in certain rituals or supernatural processes, such as the Undoing, making the one being used for power a conduit. Their are also places, such as witch catacombs where dead coven leaders are laid to rest and where rituals are done, that can nullify all powers of those who do not belong to the coven to which the place belongs. This can be easily undone if the coven leader dies, as Ruth's death after resurrecting Elena restored Aliester's powers, allowing him to telekinetically hold back a transformed Clay.
(This is horribly gross)