Demon Dragon Emperor

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

Overview
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.

When in Glass' world, Naofumi unlocked the Demon Dragon Shield and had part of the Demon Dragon's core crystal merged with the Dragon Emperor shard from his world. This linked the mind of the Demon Dragon to Gaelion's who was in the original shard. This allowed the Demon Dragon to sneak into the Shield. He offered Naofumi the chance to use All Sacrifice Aura against Kyo. Later, when the new Baby Gaelion ate Naofumi's Dragon Emperor shard both the minds of the Demon Dragon and the old Gaelion went into Baby Gaelion's head along with Naofumi's rage from the Shield of Wrath. This caused baby Gaelion to go out of control. The connection through Dragon Emperor fragments caused Filo's exp to be drained into baby Gaelion's body. The new entity flew to old Gaelion's mountain cave near Dragon Village in Melromarc.

After being shaken by Wyndia's words, the Demon Dragon shoved both Gaelions' minds out and took control of the beast. He made his demands clear and his intentions to use both Filo and Naofumi as sources of power in his global conquest. The Demon Dragon could lock Naofumi out of the Shield of Wrath and could upgrade it freely to make himself more or less powerful. He possessed the Shield of Wrath's defensive might and Dark Burning S. After being weakened by multiple Hengen Musou attacks, Baby Gaelion was able to escape with Filo. This caused the Demon Dragon to become the Wrath Dragon. When the Wrath Dragon was defeated, the Demon Dragon's mind retreated back into the Shield, saying it will stop for now.