WoW Burning Crusade - Nightbane

Nightbane was once Arcanagos, a powerful blue dragon who came to Karazhan to confront Medivh. He sensed that something was terribly wrong with the Guardian and tried to stop him, but Medivh—already under Sargeras’s influence—proved far too powerful. Arcanagos was killed and transformed into a burning skeletal dragon, becoming the creature later known as Nightbane. Long after Medivh’s death, his ruined form still haunts Karazhan’s terrace, making him one of the tower’s most tragic inhabitants: a dragon destroyed simply for recognizing the danger too early.