The youngest race on Tyria, the sylvari have a unique and mystical history. Many decades before the Sylvari came to be, a human named Ronan returned home from a long campaign only to find his family slaughtered. Having recovered a mysterious seed on his journeys, planted it near the graves of his family. He later took an oath of nonviolence, and formed, with a centaur friend named Ventari, a kind of sanctuary for anyone who wished to avoid the conflicts that enwrapped the land. Their sanctuary grew smaller in size as the war between the centaurs and humans dragged on, but before Ventari passed away, he codified his teaches on a stone tablet, which he placed at the base of the tree. A century later, the tree blossomed for the first time, bearing fruit that would eventually open to reveal the twelve firstborn Sylvari. (As befitting that background, sylvari are more correctly referred to as intelligent plants rather than the mammals that most of the other races seem to be.) Sylvari today revere Ventari's Tablet as a text that instructs them how to live their lives and pursue their destinies.
The Pale Tree from which they emerged is now the sylvari home city, but it functions as much more than that, in that it still births all new sylvari. (As the twelve firstborn existed for half a decade or so before any new sylvari emerged, all new sylvari, your character included, are referred to as "secondborn.") The Pale Tree also hosts the Dream of Dreams, a kind of sylvari collective unconscious. Sylvari that have been "born" return to the Pale Tree to commune with it, depositing their memories and experiences within the Dream; sylvari who have not yet emerged from a seed wander the Dream, learning about the world outside and preparing for their own adventures. The Pale Tree also uses the Dream to teach a sylvari such basics as the ability to read and other essential skills, ensuring that a freshly-born sylvari is more than capable of immediately venturing out into the world.
The Dream of Dreams is not without its complications, though, as the first secondborn to emerge, Cadeyrn, rejected the teachings of the Tablet and formed the Nightmare Court, which, as its ominous title might imply, seeks to pervert the Dream and corrupt it from within, eschewing the human/centaur philosophies of the Tablet in favor of a new worldview. You'll run across the Nightmare Court at the very start of the game, before you even emerge from the Pale Tree; you start the game inside the Dream of Dreams, you see, and will have to fight off some of the Court's influence before you can be "born" into your adventure on Tyria. But that, of course, won't be the last you see of them...
As you might expect from walking plants, many of the Sylvari skills are botanical in origin. Healing Seed can be cast on the ground, offering up periodic bursts of regeneration to yourself and your allies; handy during long fights. Grasping Vines will summon stalks from the ground to root your opponent, causing them to be unable to move until they slash away at the growths. The Seed Turret skill is more straightforward, as it will summon a plant that will automatically attack any enemy that comes into its range for a short period of time.
One of the Elite skills that's available to you is a kind of upgraded Seed Turret; Take Root will cause you to become completely immobile, but will spawn a few turrets to pop up nearby, multiplying your firepower. Summon Fern Mastiff is a summoning spell that'll bring a plant dog into combat, where it will poison and bleed your enemies. Lastly, and most expensively, you can use Summon Druid Spirit to draw a healing avatar to your side. The spirit will give Regeneration to you and your friends while removing conditions from them and rooting foes, but it won't be an overwhelming offensive force.
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