There are many different kinds of magic, each with special rules on acquiring the powers. Some are a blessing, some are random, some are learned, and some just exist.
Alchemy=(Alchemist) use of magical properties of materials in potions and enchantments.
Arcane=(Arcanist, Arcanight) manipulates extrarealm energies
Astrology=(Dreamer, Magi) based on the stars, sun, and moon
Dynamism=(Berserker) inherent energies in living beings
Elemental=(Elementist, Shaman) control of elements
Emotive=(Bard, Skald)
God-magic=(Disciple)
Holy=(Cleric, Demon Hunter*, Inquisitor, Paladin, Priest) power from holy realm
Illusion=(Trickster) created by goblins, art of trickery
Nature=(Druid, Sprite-singer) manipulation of plants and animals
Necromancy=(Immortal, Necromancer, Nihilite) power over death
Magic=(Mage, Spell-Blade) power from arcane realm
Mysticism=(Servants of chaos and order) the ultimate power that controls the universe
Psychic=(Marked, Psion, Seer, Siren) power of knowledge
Runic=(Runemaster, Enchanting)
Sorcery=(Demon Hunter, Hex-blade, Sorcerer, Warlock) power of the dark realm
Voodoo=(Riter, Witch) strange magic relying on rituals
Wizardry=(Wizard) magic based on study