The Knudsen clan is one of the two groups of vikings seen in the season 2 episode "Chapter 4: The Eternal Warriors" and it's adaptation "Hilda and the White Woff". Their role is the same in both continuities.
They are led by Knudsen and wield magical weapons that glow with red light when used.
Like their rivals, Torgund's clan, the clan consists of six members; four men and two women.
Their leader Knudsen is the only one that gets mentioned by name in the episode. The names of the other members are revealed in the official character sheet:
Several hundred years ago, the Knudsen clan came to the Forest of Nott to find the Medallion of Sigurd, which would forever take away their fears. They believed this would make them better warriors. Their rivals, Torgund's clan, also came to the forest for this reason. One of the clans managed to steal the medaillion from Sigurd, but fell in battle with their rivals because their new fearlessness also made them reckless. Sigurd, angered by the theft, used a potion to restore the fallen clan back to life, and wipe their memories of the battle. Since that day, the two clans got trapped in an endless battle over the medaillon. Each night, the clan that had the Medallion would be slain in battle due tot heir recklessness, after which Sigurd revived them and the battle started over, with neither clan realizing they were trapped in a repeating loop, or how much time truly passed.
When they are first seen in "Chapter 4: The Eternal Warriors", the Knudsen have the medaillon, meaning that they won the last round. They get ambushed and killed by Torgund's clan, which this night included David. The following day, David, Frida and Hilda see how Sigurd restores the fallen Knudsen clan to life. David warns Torgund's clan, and another battle follows, but since the Torgunds have used the Medallion, they lose this time around. The Knudsen Clan thus reclaim the medaillon.
After the fight, the cycle is finally broken when Hilda and Frida convince Sigurd that it was better to stop reviving the clans. Sigurd used his potion one last time to revive Torgund's clan, but this time admitted the truth and gave them the potion. The Knudsen thus got to keep the medaillon.