The Report from the Frontlines: Dragonblight can be found on the first floor of Acherus: The Ebon Hold near Highlord Darion Mograine [48.9, 29.8]. It can also be found in Death's Breach in the Scarlet Enclave [52.1, 33.8]
DRAGONBLIGHT - Prince Valanar is looking for an exceptional death knight to travel into Dragonblight, Northrend's frozen central plain, and lead an elite cadre of soldiers in a strike against the red dragonflight. "Your training is nearly complete," he said in a recent public address. "The time has come to strike against those who would protect the living! We shall show them the true meaning of Dragonblight!"
Alexstrasza, red dragonqueen and arguably the Scourge's most powerful enemy in Northrend, has been seen building up her own army as of late, though it is assumed that her efforts are aimed at the rogue blue dragonflight.