During the War of the Ancients, the red dragon Horakastrasz was placed as a sentinel along the inside of the magical barrier of the Emerald Dream (the one that prevented all but the dragons from passing through, even then with great difficulty). It was later strengthened to allow no-one through, and although Malfurion was able to penetrate it with ease, he was the first. Korialstrasz came across it on his way out to find Krasus (at the request of Alexstrasza); Horakastrasz was (at the time) a young, eagle-eyed male with a tendency to be easily distracted.