Megidramon

Megidramon is an Evil Dragon Digimon whose name and design are derived from "Megiddo Dramon". Its design is also derived from the mythological Ào Shùn (敖順?), Dragon King of the North Sea. It is an extremely wicked Digimon that is the most evil among Dragon Digimon. It is a pillar of the Four Great Dragons alongside Azulongmon, Goldramon, and Magnadramon, but its personality is so fiendish that it doesn't bear the slightest resemblance to the other three. Although it is a rare species that isn't even known to be extant, and its very existence is a "Digital Hazard", its powers were sealed away by some sort of "force". However, it is said that a great amount of damage will be exerted on the Digital World when its powers are awakened. It has a body made from Chrome Digizoid. According to one theory, Megidramon and ChaosGallantmon are the same being, and it is said that whether that wave of terror is projected as a dark knight or as a dark dragon depends on the observer.

In Ultima,

Attacks
 * Dragon Howling (Hell Howling): Releases a powerful shock wave called the "howl of hell".
 * Megiddo Flame: Attacks with flames that reduce everything to ash.