Types of Magic

Arcane

A practitioner of Arcane magic is known as an Arcanist.
Arcane magic is the easiest type of magic to use because it does not require a patron to bestow the ability, even for those without a natural connection to it. However, Arcanists are at the highest risk of being corrupted by their magic for the same reason. Arcane magic is often considered "generic" or "miscellaneous" because it doesn't have a specific specialization, instead being able to do a bit of all the other types of magic (except for Arkhyran), albeit not as well. It is not unheard of for an Arcanist to specialize in a specific type of magic, but this approach is typically discouraged among Arcanists since it doesn't play to the strength of Arcane magic.
The risk of corruption was the main driving force behind the creation of Arcanists' guilds, which are intended to both teach Arcane magic, and prevent their members from being corrupted by it.
Practicing Arcane magic is entirely illegal in some places, and heavily restricted by law in many others. Even where there aren't legal restrictions, Arcanists' guilds typically have strict internal regulations.

Nature

A practitioner of Nature magic is known as a Druid.
Nature magic is, obviously, magic pertaining to nature. Many people think that this means plants and animals, and they are not wrong, but Nature magic encompasses all of nature. This also includes things like fire, ice, wind, and stone, as well as things like gravity and magnetism.
The ability to use Nature magic can be bestowed upon mortals by powerful beings connected to it, such as Hamadryads. An alternative name for Nature magic is Elemental magic.

Divine

A practitioner of Divine magic is known as a Cleric.
Divine magic is the magic of the gods. The ability to use Divine magic can be bestowed upon mortals by any god. Unlike most other types of magic, what exactly Divine magic does depends on the specific god that bestowed it. For instance, a Cleric of a war god might be able to summon a weapon, while a Cleric of a feasting god might be able to summon food. Divine magic can have significant overlap with the other magic types, but an individual Cleric will ususally have a quite a limited repertoire.
There are various factions among the gods, known as pantheons.

Eldritch

A practitioner of Eldritch magic is known as a Witch.
Eldritch magic comes from various mysterious beings. These beings are not gods, though some suspect that they hold a similar level of power. It is quite common for people, especially those not learned in the ways of magic, to believe that these beings are all in league with each other. The reality of the situation is significantly more complex, with various factions existing as well as many who are independent. It is often quite difficult to intentionally initiate contact with these beings, and as a result, Eldritch magic is somewhat rare compared to other types. Like Divine magic, the exact form that Eldritch magic takes depends largely on the being that it comes from.
Because much Eldritch magic comes from The Moon, many people believe that Eldritch magic in general is more powerful at night, despite the fact that this only applies to magic from The Moon. Thus, some people refer to it as Dark magic or Black magic. It is also commonly believed that many Witches are enthralled by their patrons. This is not as common as many believe it to be, but is common enough that it is something to be wary of. Because of this, and because of the enigmatic nature of these beings, Witches are quite often distrusted, and the word Witch has a negative connotation in many places.

Demon

A practitioner of Demon magic is known as a Warlock.
Demon magic comes primarily from Irkalla. It is considered not natural to Aevorea and many consider it to be evil. As such, it is taboo and illegal in many places. The ability to use Demon magic can be bestowed by powerful demons with a natural connection to magic. The most notable of these are the Princes of Irkalla. It can also be bestowed by the gods of Daemonium, who were separated from normal Divine magic when they were banished. Demon magic typically encompasses things in or relating to Irkalla, such as summoning Irkallan creatures. As such, it is sometimes referred to as Irkallan magic.

Fae

A practitioner of Fae magic is known as a Draoi. (Plural: Draoithe)
Fae magic comes from Faerie. Two types of beings can be patrons of Fae magic: the Tuatha and the Fomorians. It is believed that the Firbolgs also had this power, but none have been seen in many millennia. This type of magic largely involves illusions, enchantments, mental manipulation, and curses. Because of the source of Fae magic, as well as the kinds of spells it is best suited for, Draoithe are often distrusted, especially by those with knowledge of the Fae.

Arkhyran

A practicioner of Arkyran magic is called a Necromancer.
Arkhyran magic comes from Arkhyros. Arkhyran magic is primarily focused on necromancy and disease. It is, unlike other magic types, constantly active across the whole of Arkhyros, for unknown reasons. Undead raised by Arkhyran magic gradually grow in intelligence, and eventually become able to use it themselves. The exception to this is those who had inherent magical ability before death, as they already have these capabilities immediately upon being raised. Arkhyran magic is commonly called Necromancy.
Necromancy is the most taboo of all magic types, being illegal everywhere but entirely lawless places. Necromancers are nearly universally hated, even by other outcast mages like Warlocks. Between this taboo and most people not knowing how to get in touch with Arkhyros, Necromancy is by far the rarest type of magic.