Catastrophe Dragon Lord

Catastrophe Dragon Lord (カタストロフ・ドラゴンロード) is a Dragon Lord, one of the most powerful dragons in the New World.

Background
It seems that the Catastrophe Dragon Lord was already dead as the "Thousand Leagues Astrologer" of the Slane Theocracy predicted its revival.

The Undead King Arc
When the Catastrophe Dragon Lord was predicted to revive, the Slane Theocracy dispatched the Black Scripture, one of the Six Scriptures to deal with the situation.

The Bloody Valkyrie Arc
The Black Scripture had already reached the Forest of Tob along with Lady Kaire searching for the Dragon Lord to subjugate it using Downfall of Castle and Country, but were forced to abandon their mission after they were attacked by Shalltear Bloodfallen.

The Ruler of Conspiracy Arc
According to the Cardinals, the threat of the Catastrophe Dragon Lord is still at large. With most of the Theocracy's forces occupied and indisposed, the Cardinals hope to resolve the situation by using Downfall of Castle and Country on the said Dragon Lord if it does appear. They were hoping to use it as a vanguard against the Sorcerer King.

Abilities and Powers
The Catastrophe Dragon Lord's power is unknown, but it should be noted that the Cardinals sent all thirteen members of the Black Scripture armed with a World Item to defeat the Dragon Lord, which speaks volumes of its power.

Trivia

 * Prior to Shalltear getting mind-control, Catastrophe Dragon Lord was supposed to be the main target for that kind of effect under Downfall of Castle and Country.