Knut Caine was a terrorist obsesed with Norse mythology who recreated many of the Asgardian tales his way ,transformed by Loki`s dagger he became what he wanted the most ..The Mad Viking a copy of Loki himself (sort of ). He battled the Hulk ,Henry Pym and the Wasp ,but was killed by a bite from Jomrungandr (a snake he transformed  ) .

There was another Mad Viking Named Joesfsen

who was a dock worker that saw today man as weaklings. He fought and was killed by the Man-Thing .His first appearance was Man-Thing # 16(1975)