It is a common belief that magical energy (Chra or Mana) comes from the gods whether it is given to the faithful (Priests) or directly tapped into (wizards). How the energy is received has long been questioned, but it has always been assumed that the obelisks are the key.
Obelisks are stone structures anywhere from five to fifty feet in height that are dedicated to one of the gods. They act as altars and worship sites, but they are much more that this, they are mana conduits. Vitae Laenum Nem I, whose source is unknown and veracity unquestioned, explains that mana is a life energy that inhabits every living thing. This energy can be given or taken with significant consequences; if taken away, the living will die. When given in great quantities manipulation of reality and meta-physical laws is possible, this practise, is better known as magic.
Every creature has a finite amount of frequency that is contained within their life force. Creatures from other worlds have an “excess” of this energy they need and can bestow it to another without being harmed. The mana from the gods is incomprehensible, and they radiate it outward from the heavens. it is important to note that the gods do not give magic, only the energy used to cast spells. Mortals can sense this energy most often through their hearing, seeming to be a soft heavenly chorus of humming known as the frequency, and is the most recognized telltale sign of magic. After manipulation of the energy fields, there is often a kaleidoscopic rainbow-like swirl around either the source or affect that lasts for a few minutes.
Spell-casters tap into the frequency to cast spells, manipulating this energy via various means: clerics use their holy symbol, wizards invoke ancient words of power, sorcerers seems to be mini-conduits themselves. Clerics believe wizards directly steal the frequency, and for this reason there is a bad blood between the two. There are no gods of magic or wizards known on Nyssa for this reason. Sorcerers are tolerated, as they are believed to be gifted. Wizards tolerate clerics, they think the faithful are toadies that offer coin and hollow words for favours, yet they know that if clerics ceased their acts of piety, the energy for magic, potentially would fade away.
It was the gods, wanting to help their followers, that began to send some of this energy to the mortal plane. Because these heavenly beings are unable to directly enter the mortal planes, they sent their angelic hosts to teach their followers how to build the first and maintain control of the obelisks. In the space between, the chra or raw magical energy is in oceans, swirling in currents and eddies of raw unblemished energies. (Mana comes from living creatures, chra does not, but it can be used just the same.)
Even if unmanned, obelisks conduits tap into the astral to release the energy in the mortal plane as a small outward invisible stream. Interestingly even though obelisks are dedicated to one power, all priests regardless of the god worshipped can gather the energy through any obelisk. Many are virtual temples with hundreds or thousands of faithful coming daily or weekly to give praise and sacrifices to the power they worship. Some do not have resident priests and may be visited only once or twice in a year. They are always outside, though they may have buildings near it. Most are in cities often within site of other obelisks dedicated to other gods.
It is the reliance on obelisks which is both a strength and hindrance for clerics. Many obelisks can give increased energy, power or insight, especially to their faithful. But as they get farther away from obelisk, a priest`s power wanes. There are places, such as in the Hopeless Sea, that magic cannot be cast simply because there is no nearby connection to the obelisks. While wizards and sorcerers are far less reliant on these devices, they too can fall prey to being far enough away from an obelisk that they start to lose their capacity for highest levels of magic.
Obelisks can be created in various ways, the most practical is to carve one out of stone, then have a priest bless it. These are the most common and are often great works of art, sculpted over a long time and financed by the faithful. They often have pictures of the gods or their forms on one side as well as the “common” located on another. Others appear due to wondrous acts of faith, appearing overnight as a sign of favour from the god. Lastly they can be created through spell for high-level priests who wish to spread their religion or begin a monastery.
Yet, as important spiritually as they are, an obelisk does have a physical form and it can be destroyed. It will not happen by magical or natural means. Lightning will not strike it and spells cast to harm it merely reabsorbs the energy used to cast the spell itself. Deliberate acts of violence by mortals can destroy the obelisk as if it were a mere stone monument. Most have the faithful as well as other guardians protecting them and it is only after a long protracted struggle could most obelisks be left vulnerable to such attacks.
Every obelisk can be used as a exiting teleportation site by any outer planar creature. Creatures can only step through if they are allied to the dedicated god and there is a cleric willing the creature to step thru. There are other unique magics such as resurrection spells which can only be cast near an obelisk.