Who is Stradivarius from Everlost and what is their importance?

Stradivarius (Vari) is a young boy, who spends a great deal of time with Mary. He has a talent with a violin, which he plays for Mary whenever she ask him to. Vari is extremely jealous when Nick begins spending time with Mary. When Mary loads all the children on the blimp, she inadvertently leaves Vari behind. He takes command of the McGill's abandoned ship.