Demon Dragon Emperor

The Demon Dragon Emperor is the Dragon Emperor fragment of Glass' World.

Gaelion-Possessed Form
As the Demon Dragon Emperor possessed Gaelion, it created a 20 meter high, fully-grown dragon form out of black sludge. It's eyes were filled with darkness. As the sludge solidified, it took on a purple hue. The Demon Dragon's new look reminded Naofumi of his Shield of Wrath.

Post-Revival
After being revived by the heroes, the Demon Dragon Emperor looked like a purple palette-swap of Gaelion. Revived in a female this time, she initially had the same small infantile body with tiny wings and a fat tail. However, the look in her eyes were quite different from either forms of Gaelion. From a glance Naofumi could notice that she harboured a lot of ill-will.

Personality
The Demon Dragon is a vicious, ruthless, and highly intelligent megalomaniac. His desire to rule the world stems from the belief that those who currently run the world are unworthy. Worst yet he thinks nothing about who he has to hurt or make an alliance with in order to secure his own power thinking nothing of taking over the body or the infantile Gaelion or converting Filo and Naofumi Iwatani into sources of power by integrating them into his body.

Background
The Demon Dragon Emperor is a fragment of the Dragon Emperor from Glass' world that tried to take over the said world and subjugate the people. The reason for this is because the Demon Dragon thinks that humans and thus other similar beings are selfish, hateful, foolish, and unfit to lead, unlike himself of course.

The threat was handled by the Hunting Hero, Kizuna Kazayama, who was summoned to slay the Demon Dragon. After his defeat, the Demon Dragon's body was used for resources. His body unlocks the Demon Dragon weapon in the Holy Heroes, who all use it as their new default weapon due to its good stats, abilities, low-level requirement, and easy ability to use.

Trivia

 * Drops from the original demon dragon's body unlocked the Demon Dragon Shield.