Basic Primer for those interested in Warcraft Magic. Very basic explanations.

Their is no one type of magic, but several equally viable types of magic. Each with their pros and cons.

Arcane: the power of Order. Arguably the most powerful of all the magic types, but also the hardest to master. Can do almost anything so long as you have the knowledge and power to execute the spell. The most traditional type of magic in the setting.

Nature: power of Life. Almost wholly used by druids. Manipulating nature, communing with animals, shapeshifting into animals, communing with forest sprits, and healing corruption. Also allows access to the Emerald Dream, a primordial realm of nature that connects to every dreaming mortal on Azeroth.

Holy: power of Light. Dedicated to healing, protecting, and striking down the wicked. You physically cannot use this magic if you intent to harm innocents. If the caster believes, even for a second, that the spell will harm an innocent, the spell fails. Full Stop. The caveat is that its all based on perspective. If the user genuinely thinks that a person is wicked, even if they are objectively innocent, then they can call down the light to strike them down. That's how fanatical groups like the Scarlet Crusade can go around slaughtering entire villages with Holy magic.

Fel: power of Chaos. Demon magic. Fire and brimstone. Fueled by souls. Highly corruptive to the user. Most stereotypically evil type of magic. Arguably the easiest magic to accumulate lots of power very quickly with. Also the easiest power to lose control of and kill yourself with, not counting when your demon sugar daddy come knocking for that soul you promised.

Death: power of Death. Necromancers. Basically necromancers and death knights. Command the legions of the dead. Control and inflict festering plagues and epidemics. And even achieve pseudo immortality by becoming a Lich. Also, continually use will eventually rot the user from the inside out.

Shadow: power of the Void. Power of insanity and mental corruption. Very powerful. also very dangerous to the user. Primary magic of the Old Gods (Warcraft Cthulhu) and their servants. Users just as likely to become jabbering mad men as they are to wield destructive power. Look into the abyss, and the abyss stares back.

Elemental: Magic of the elements (Fire, Air, Water, Earth). Shaman magic. The quirk is that the power is not 'yours'. It's the elemental you've formed a pact with. No risk of corruption, insanity, or anything bad for the user. Worst thing that could happen is an elemental refuses to lend you their power. Said elementals may also refuse to work with a shaman who is in pact with an elemental of an opposing element.  A shaman with all four elements at their call can be called both an powerful magic user and an accomplished mediator.

Note that mages or other magic users are not restricted to only using one school of magic. Mixing and matching tends to lead to more powerful magic users, but you still have to deal with the ups and downs of both systems. 

For example: Priests can use Holy magic to heal and Shadow magic to attack. Warlocks tap into Fel and Shadow magic for greater power but are doubly vulnerable to being corrupted in both body and soul. Druids cast both Arcane and Nature magic to offset the deficiencies of both. 

[Note: timeline uses the Opening of the Dark Portal as Year 0]

-1 : Syllia is found by Ameria in the Eversong Woods and is taken in as her daughter.

0: Dark Portal Opens, First War begins

3: Stormwind is sacked. First War Ends in Horde Victory. Syllia is 4 years old.

4: Second War Begins.

5: Horde Siege of Silvermoon. Orgim Doomhammer forced to withdraw to escape encirclement by Alliance forces. Amani forces routed. Quel'Thalas joins the Alliance. Battle of Lordaeron begins.

6: Second War ends in Alliance victory. Orcish Interment begins. Syllia is 7 years old.

8: Events of Beyond the Dark Portal occur; Dark Portal reopens due to actions of Ner'zul, Alliance forces launch counter invasion to Orc homworld, Dark Portal is sealed by Alliance forces on the far side of the portal as Draenor is torn apart by magic, Alliance expedition assumed lost.

9: The Alliance splinters; the Kingdoms of Gilneas, Stromgarde, and Quel'Thalas leave the Alliance over disputes for the payment of Orcish interment.

10: Events of Day of the Dragon occur; Alexstrasza freed from control of the Dragon Maw Orcs and returns to Wyrmrest to recover. Syllia Dawnguard is accepted into Dath'Remar Academy.

11: Syllia Dawngaurd becomes the apprentice to the red dragon Siristrasza; Syllia Dawngaurd is approximately 12 - 13 years old.

12 - 19: Orcish liberation from Interment camps. Thrall declared Warcheif of the new Horde. Cult of the Damned formed by former Kirin Tor Arch Mage Kel'thuzad.

20: Events of Reign of Chaos begin. Syllia Dawngaurd is 21 years old.