Ysera is the little sister of the dragon queen Alexstrasza. Ysera is the Green Dragon Aspect and was blessed by the titan Eonar giving her a portion of natures influence. She was charged with the protection of the emerald dream. When she was granted her powers she fell into an eternal trance. Much like her sister Ysera dislikes conflict and will try to avoid it unless their is no other choice. When in combat she normally trys to disable her opponents instead of killing them, she uses her green breath to put her foes to sleep then banishes them from her realm. She can also attack the mind as seen in the book Day of the Dragon.
In World of Warcraft Ysera is currently in the emerald dream coordinating the battle against the nightmare. She can be found sleeping in the Emerald dragon shrine within dragonblight in northrend.