Tannin is a dragon and formerly one of the Six Great Dragon Kings. He chose to become a devil so he could participate in the Rating Games and fight various beings, and acquire a territory that grows the dragon apple, a fruit a certain race of dragons have to eat to avoid extinction, due to the fruit becoming rare in the human world. He was reincarnated as a devil by Mephisto Pheles, becoming his queen.

Tier: High 7-A

Classification: Dragon, Reincarnated Devil, Former Dragon King

Powers and Abilities: Superhuman physical characteristics, aura, flight, summoning, shapeshifting, invisibility, rage power, breath attack, teleportation, forcefield creation, enhanced senses, fire manipulation, size manipulation, extrasensory perception, large size (Type 1), immorality (Type 1), non-physical interaction, resistance to magic (Dragonscales have resistance towards magical attacks)

Attack Potency: Large Mountain level (Blew a section of a mountain off with a casual attack. Stated to have Satan-class power, putting him in the same ballpark as Katerea Leviathan)

Speed: FTL (Easily kept up with Bikou, and should at least be comparable to other Dragon Kings like Vritra)

Lifting Strength: At least Class 10 by virtue of his size

Striking Strength: Large Mountain level

Durability: Large Mountain level

Stamina: High (Continously "played" with Issei for a whole day without looking winded at all)

Range: Extended melee range, likely several hundreds of meters with his fire attacks

Standard Equipment: None notable

•Optional Equipment:

°Phoenix Tears: A small bottle containing the tears of the members of the House of Phoenix. It can be used to heal serious injuries and reattach limbs.

Intelligence: Unknown

Weakness: Dragon-Slaying weaponry (Even though Holy Water is a weakness to the majority of devils, Tannin doesn't have that weakness due to being a dragon)

Notable Attacks and Techniques:

•Dragon Flame: Like all dragons, Tannin possesses the ability to breathe attacks of a specific nature, particularly fire in his case.

•Size Alteration: Tannin can transform into a mini-Dragon form in order to fit into small places like a building.