Rath Illuser

History
He is the Dragon Knight of Fire. One of his hobbies is killing demons, he would often get excited just by hearing the word including a habit if there are any demons. He uses the Fire Dragon Sword and later the Light Dragon Sword. It was also revealed that he often breaks things that are given to him because he goes demon hunting to much. Also he boasts about being able to use Fire and Ice magic along with a strange ability to make temporary copies of himself and being able to absorb others' powers and also having special ties with the Light Dragon. It is also known that he wasn't the true Dragon Knight of Fire. He also harbors a great amount of self hate which he frequently projects to others. It was revealed in Volume 19 that he almost commits suicide by Thatz's Earth Dragon Sword. It also takes a special person and a large amount of effort to break his many masks. It is also shown that he is the only heir to the Dragon Lord. He is also somehow related to the Demon Lord and think that he should not be one of the living. Cesia and Rune are two of the people that he wil act naturally around. When he and Cesia traveled together to find a way to revive Crewger, Rath's Demon Dog, he had started developing feelings for her. Since then he would protect her from demons that would go after her.

Rath used to be an evil spirit that had possessed the dead body of the Dragon dog, Illuser. Lykouleon used his blood to turn it into one of the Dragon Tribe. After going to Nadil's castle to rescue Cesia with Rune and Thatz, Rath is captured and Cesia releases all the souls that were held inside of Rath, most notably Gil and Bierrez, and Rath disappears. It is unknown whether or not Rath is dead at this point or not and the story seems to indicate that Cesia will bring him back again at some later point.

When Cesia finally revives Rath once more, he goes back to Nadil's castle where Nadil reveals that Rath is the Demon King of the East. This finally explains Karl's inexplicable loyalty to Rath and Rath's ability to continually return to life in different bodies. Rath uses Rakeita, the magical gun, with the help of the Dragon lord and Dragon empress' dragon eyes. In the end, Rath and Cesia become the Dragon Lord and Queen.

