The Supernatural in Gaia
Gaia is a land where there are several supernatural creatures and people with supernatural abilities. But in the end most of these abilities fall under a certain classification.
Gnosis: The Primeval power, Gnosis is, in more than one sense, a measure of one's importance in the world. Those with a really high Gnosis can do incredible things just by wanting it. From controlling fire, to being able to predict the movements of an enemy or travel through different planes of existance. The higher the Gnosis, the more powerful these abilities are, with higher beings being able to even give some powers to those who accept them.
Magic: Using Ezervaju, the main energy that runs through creation, some people and creatures can control this energy to perform incredible feats. However not everyone can control the Ezervaju. Only those known as Gifted can do so. The Gift is something that seems random, and most people who have it never know. For the mortal races, the Gift is something truly unique. Only one person in a hundred THOUSAND people is Gifted. The only exceptions are the Sidhe. As far as everyone knows, all Sidhe are Gifted.
In order to use magic, Gifted people have to use already created spells, or they have the risk of going out of control. No one knows who created the Spells, but they are divided into eleven "Paths". The six elemental Paths (Fire, Water, Earth, Wind, Light and Darkness), Essence (mostly the Path of Nature), Illusion, Creation, Destruction and Necromancy. There are also several Minor Paths, composed by spells that can be found in several different Paths, and some Spells without a Path.
There are also different ways to use magic. Most Gifted simply use it by doing some gestures and saying certain words (that can vary from Gifted to Gifted, even for the same Spell. It is thought that the words and gestures used, as well as the Gifted's personality is what gives is appearence to the Spell. So one Spell of Fireball might look like just a Fireball, while another Gifted can use that same Spell and make it look like a fire dragon flying at its objective). Some are so powerful or trained in their abilities that can forego the use of words and gestures without disminishing their powers. Some might have differences in their Gift, and be forced to use special ingredients for their spells, while others use special scrolls to store their spells until they need them. And those are just a few examples.
Psychic Powers: There a few individuals in each race with enough willpower to just make reality change, allowing them to move objects with their mind, create fire, slow time or who knows what. They are very few, but it is not unknown of a Gifted showing also Psychic Powers...
The Mastery of Ka: Ka is a vital energy that runs thorugh every living thing. Sometimes called a subproduct of Ezervaju, those who master the Ka of their bodies can get incredible powers. Ka masters are known for feats such as flying, defeating groups of soldiers with a single blow, having superhuman strength or agility and so on. It's supposed anyone can master Ka with enough training, but only those truly dedicated to it achieve its greatest powers.
Summoning: Not really a power of it's own. Summoners can do so by using Ezervaju (either by training in the complex arts of Summoning or by using ancient rituals), although they don't need to be Gifted for doing so, or using Ka as a mean to create a Bond between them and another entity. Each method has its advantages and drawbacks.
The arts of summoning were the first used to summon creatures and entities, and although they remain the most efficent (they last longer, are more powerful and can be used to make pacts with beings with a high Gnosis), they need a lot of dedication, and only those Gifted or those that only try to master a certain part of summoning (like calling a creature, binding it to an object, banishing it...) can really hope to be able to use this art with really powerful beings.
Rituals can be done by anyone with the required knowledge, but usually need something to power the ritual, special preparations to be done and more. On the brighter side, there are rituals that mimick other effects of magic, not only summoning.
Finally, using Ka needs the entity you are calling to agree to the call, and this kind of summoning can't last for long (even masters can't maintain the Bond for more than an hour), as Ka isn't Ezervaju after all.
Needless to say, all types of summoning take their time. From a few seconds to even days or weeks. And in the case of rituals, sometimes even years.