Acnologia

The Black Dragon (黒龍, Kokuryuu) is a powerful dragon that appears to be flying around the continent or the world. Unlike the other dragons that have withdrawn from human affairs, the Black Dragon has not. While the other dragons appear somewhat friendly to humans, the Black Dragon is most certainly an enemy to all humans.

When Gildarts Clive took on his "100 year quest," he ran into the Black Dragon on the third year on Zonia mountain. In an instant, the Black Dragon took Gildarts's left arm, leg and an unspecified organ, leaving him to die before flying away, with Gildarts managing to survive with difficulty.