A series of tests and challenges that must be completed before a boy can be declared a man and warrior. This practice on the Planet Nilfeheim is taken very serious and is part of their Ancient traditions.
While only sons of Clan lords take the challenge, it is actually open to anyone and even females. Sif, Eric's first wife takes the challenge and is accepted as Warrior.
(Elena takes the challenge as well and later becomes the first female Clan Chief in Nilfeheim history)