|Nicknames||Chaos Karma Dragon|
|Hair Color||Pale Blue|
Tiamat has the appearance of a blue Western Dragon.
In her human form she has long beautiful pale blue hair and a cold atmosphere that radiates from her beauty.
Not much is known about her personality, besides the fact that she hates Ddraig for borrowing her treasure, which was destroyed into several pieces and scattered.She also shifts the blames onto the possessor of the Boosted Gear, Issei Hyoudou, saying they need to take responsibility for her treasure or she will burn them to death.
One of the Five Great Dragon Kings, Tiamat is one of the few legendary Dragons that are still active. She is known to be rampaging around the world occasionally. At some point in the past, Ddraig had borrowed Tiamat's treasure for his upcoming battle with Albion and was accidentally destroyed during the fight. Since then she has been chasing after Ddraig and his possessors for a long time, to retrieve her stolen treasure.
While Tiamat has yet to appear in the series, she was mentioned in the side story "The Familiar's Requirements" by the Familiar Master as a candidate for a powerful Familiar.
She was mentioned once again when Issei and Azazel were talking about the Evil Dragons. During the conversation, Tiamat was said to be the strongest among the Five Great Dragon Kings and has blended in well with the current world and living as she likes.
Tiamat made her first official appearance in Volume 19. She appeared in the Rating Game between Diehauser Belial and Riser Phenex after the retiring system didn't work on Riser and Ravel. It was revealed that Tiamat acts as the secret judge/administrator for the Rating Games and only appears when something unexpected or malicious things happen. She does this as she is indebted to the Maou Ajuka Beelzebub and has appeared only twice in the past to resolve things for the games.
At the end of Volume 20, Tiamat accompanied Ajuka who was conversing with Shiva about Trihexa's reincarnation, she shows Shiva a blue mobile phone noticing that it was related to a Longinus.
Red Dragon Emperor of the Blazing Truth × White Dragon Emperor of the Morning Star: The True Dragon(s) of the Kuoh AcademyEdit
She returns in Volume 23 along with Nakiri and Millarca and demands that Ddraig give her back her treasure that he stole. She threatens him and Issei to return it or she will burn them. She cannot participate in the Rating Games due to being part of the tournament's organisation.
Powers & AbilitiesEdit
Shapeshifting: Tiamat has the ability to shapeshift from her Dragon form into a human form.
Immense Strength: The strongest Dragon King out of all the Dragon Kings. According to the Familiar Master, she has Satan-level powers. Tiamat's anger is strong enough to bring Ddraig, a Heavenly Dragon, to cower in fear.
Fire Breath: As with many other Dragons, Tiamat has the ability to breathe fire.
- Tiamat's name is derived from the Babylonian sea goddess Tiamat. Also, Tiamat's title, the Chaos Karma Dragon, is derived from the fact that the mythological Tiamat is a chaos monster.