Urdwigia

Urdwigia (ウルドヴィジア Urudovijia), also known as the Colossal Lightning Dragon (傀雷竜 Kairairyū), is a thunder dragon, who became the right arm of Xiaoyu Lei.

Personality
Urdwigia could be said to be a prideful being, typical of a dragon. Though defeated and brought back as a spirit, he still maintained a high regard for himself. In order for Easlies to make a contract with him, as her summon, the dragon demanded she reclaim his body that she sold. His reason for this was due to his respect for strength, as he did not want those weak to do as they please with his body.

Background
In the Other World, Urdwigia was hailed as a dragon who bathed the world in electricity. Urdwigia was encountered by Easlies Swordfrail who slew him. The necromancer would then form a 200 year contract with the dragon. However in order to do so, Easlies was required to buy back all his remains from the guild she initially sold to. Due to Corpse God being the pupil of his slayer, he permitted the young necromancer to take any part of his corpse and do as he wished.

After Death
On Earth, right was given to Xiaoyu Lei by Corpse God, after the bodyguard lost his prosthetic in an encounter with Majiri Agakura. The arm acted as a contract between the two in forming an alliance in order to protect Polka Shinoyama.