Nidhogg is a legendary enemy that lives in the Unlimited Neutral Field.
Nidhogg is an extremely dangerous and powerful monster who will follow all orders by Sulfur Pot while under the effects of his Enhanced Armament. However, after being freed by it, he instinctively betrayed his master proving that it cares for no one besides itself.
Nidhogg is known as a legendary enemy who more powerful and vicious compared to regular ones. He was eventually tamed by Sulfur Pot by his enhanced armament, Mystical Reins which allow the user to tame any monster that he chooses. With no choice, Nidhogg was forced to follow orders from his new master.
Nidhogg's appearance is similar to a large dragon that is many times the size of a regular Duel Avatar. His body has scales that protrude all over. He has two horns attached to the top of his head with another one acting as his nose. His eyes are red with yellow pupils.
Dusk Robber (Side Story)
- Scorching Inferno: As pointed out by Sulfur Pot, when a high-level legendary enemy is tamed they gain a killer move. Scorching Inferno allows Nighogg to shoot a blast of fire from his mouth; a very powerful killer move. It did a lot of damage to Black Lotus even though it barely hit her.
- High Invulnerability: Nidhogg's body is covered in extremely durable armor; strong enough to deflect Crimson Kingbolt's tapping screws and survive his barrage of missiles.
- Swimming: Nidhogg can use his tail to swim in water.
- In Norse mythology, Níðhöggr (Malice Striker, often anglicized Nidhogg) is a dragon who gnaws at a root of the World Tree, Yggdrasil.
- Nidhogg had one of his fangs cut off by Black Lotus.
- When the Mystical Reins were cut off by Lotus, Nidhogg devoured Sulfur Pot who put them on him which suggests that the reins enslave Legendary Enemies against their will.