Arcane

Arcane magic is the gift of titans to the world, a gift that comes with the highest price. Thousands of years ago, the titans placed the Well of Eternity  in the center of Kalimdor  to serve as a source of restoring, life-giving energy. They intended that the Well's energies would empower life of all forms to emerge on Kalimdor — plants, animals, monsters, races. After a time, the titans left Azeroth, leaving Kalimdor in the hands of the five dragon Aspects. Yet the Well of Eternity proved too great a lure to remain hidden for very long, particularly from Sargeras  and the Burning Legion.

Children of the Stars
The Well was discovered by the Kaldorei, who were later known as night elves. Ever eager to uncover secrets hidden in dark places, the Kaldorei listened to the Well as it promised to give them great power. At the Well's behest, the Kaldorei learned spellspeech and used it to weave the first arcane spells. Within decades, Kaldorei mages had attained sufficient mastery over arcane magic that they built a great civilization. They founded the imperious city of Zin-Azshari, from which they extended their domination over most of Kalimdor. Ultimately, the magic corrupted them. The Kaldorei had been a simple folk who gazed blissfully at the stars, enjoying the immortality given to them by the Well, but their haughtiness robbed them of that gift forever. Each succeeding generation became prouder and more decadent, and the lust for power only made the Kaldorei more of a beacon to the lords of the Twisting Nether. Finally, their greatest mage, Queen Azshara, cast a spell in the heart of the Well of Eternity itself — and a way was opened for evil to invade the world. Through Azshara's breach came the Burning Legion, the most terrifying warriors in existence. This fiendish horde ravaged Azeroth, pillaging entire kingdoms, destroying all that stood in its path, mocking anyone who begged it for mercy. When the Burning Legion ravaged the land, great heroes recognized that arcane magic posed a continuing threat to all living creatures, so they elected to destroy the Well of Eternity and put an end to arcane magic forever.

Unfortunately, among their number was one Illidan Stormrage, an arcane spell caster who dreaded the thought of losing his powers. Secretly he stole some of the well's water and used it to create a new Well of Eternity at Mount Hyjal, thus preserving the power of the arcane. This theft allowed future elven generations to follow in the footsteps of Illidan and Queen Azshara. These elves called themselves the Quel'dorei, "the high elves " (for they believed that their mastery of the arcane elevated them to higher status). They also taught the arcane arts to the newly discovered race of humans, who showed a natural aptitude.

Human Magi
These human mages, however, were even more reckless than the night elves had been. The high elf mages warned their human pupils that magic was addictive, but the acolytes dismissed any suggestion that the tragedies that had befallen the elves would also afflict them. The humans were no better at resisting corruption than the elves had been, and eventually the arrogance of wizards brought the Burning Legion to Azeroth once more. Once again, great acts of heroism were needed to spare Azeroth from destruction.

Orc Warlocks
Elsewhere, on the orcish home world of Draenor, arcane sorceries corrupted the once noble race of orcs, transforming them into the Horde, a nigh invincible army. After ravaging their home world, the orcs came to Azeroth; and with their warlocks, they waged two great wars against the races of human, elf and dwarf. The orcs failed to seize control of Azeroth; during these wars, Draenor itself was utterly destroyed, and the orcs were forced to relocate to Azeroth.

In the wake of the Third War against the Scourge and Burning Legion, the orc Warchief Thrall has rejected arcane magic and embraced his race's traditional shamanistic ways. Yet orc warlocks still walk the world, and demons whisper in their ears each time they cast a spell. Neither human nor high elves have abandoned the pursuit of the arcane; if anything, the defeat of the Burning Legion at the Battle of Mount Hyjal has fed the arrogance of many spell casters, who believe the world is now protected from demonic influences and that arcane spell casters may practice their art in relative safety. Nothing sows the seeds of the fields of tragedy quite like arrogance

Arcana domain
The arcana domain, or magic domain as it is sometimes called, (not to be confused with the spell domain) is a deity domain that grants divine spellcasters prayers connected to the power of the arcane. They may, as part of their training, gain the ability to use wizardly implements such as scrolls, wands, and rods. Arcana domain prayers 1st level 

Magic Missile

2nd level 

Mirror Image

3rd level 

Identify

4th level 

Dispel magic