Dark Knight of the City-State Alliance

Dark Knight (勇者) was a warrior who hailed from the Karsanas City-State Alliance.

Background
The Karsanas City-State Alliance considers him to be their country's national hero.

The Invaders of the Large Tomb Arc
When the workers discuss potential individuals who are said to be very powerful in their own right, Brave was mentioned as one of the strong pure swordsmen on their list.

Abilities and Powers
Dark Knight was considered to be a strong swordsman alongside Brave in the City-States.

Trivia

 * In the Web Novel, he is absent from the list of warriors the workers list out.