Dahaaka has a mostly humanoid appearance, with the exception that they has no head and their facial features are in what would be their chest. Dahaaka has a wide large mouth and a long tuft of pink hair coming from the top of their "head". In the forehead has a red mark shaped like a crescent moon against a waning moon, forming an x-pattern.
Dahaaka is gluttonous and rather impatient, as seen when he ditched his comrades in the Egg Rock to eat humans.
3,000 years ago
The Six Knights of Black were part of the battle against the four races in the Sky Temple, where an Indura brought destruction. When the victory of the Demon Clan seemed certain, the Great Oshiro appeared and defeated the Indura, allowing the Goddess Clan to seal the Six Knights of Black, the Indura and other demons within the Egg Rock.
He escapes the Egg Rock and after tricking some Celestials, Dahaaka eat their souls. Zoria fights him and Dahaaka manages to overwhelm him. Meliodas kills Dahaaka after using Full Counter to reflect the power of Thunder Carnival back at him, freeing all the souls he devoured.
His soul is later used by Bellion to revive Baruja.
Abilities and Equipment
As a member of the Six Knights of Black, Dahaaka is stronger than an average Demon. He shows the ability to generate and manipulate electricity.
- Voltaic Whip: Dahaaka directs an electric discharge through his tuft. 
- Thunder Carnival: Dahaaka releases a barrage of electric spheres over his opponent. 
- Transformation: Dahaaka has the ability to change his appearance, the extend of which appears to be limited. However, he was shown to have changed the tone of his skin and hair to match that of the Celestials to trick them.
- Zoria vs. Dahaaka: Win
- Meliodas vs. Dahaaka: Lose
- Dahaka may have been named after the Zoroastrian demon, Aži Dahāka.