In Völsunga saga it is said that Volsung , grandchild of odin , is king in hunland . I dont get what is the connection between huns and the viking mythology . From this point many other questions rise ,because huns had interaction with the germanic tribes in central europe around 3rd & 4th century. Does that mean norse mythology decents from these eras?
Völsung saga is written down in the 13th century, but is based on a much older cycle of stories from the iron age, involving the Burgundian and Huns in central Europe. So originally there is nothing Scandinavian or "viking" about the stories. The same cycle of stories is the basis for the medieval German epic Niebelungenlied, and for the heroic poems in the Elder Edda.
Norse mythology have different origins (the Aesir share indoeuropean roots with Greek, Roman and Indian gods) but have become interleaved with the Nibelungen stories.