Dragon Ball was based on the Chinese folk tale "Journey to the West" where a Buddhist monk travels from China to India trying to get more accurate Buddhist texts. Goku is based on a character known as the monkey king, who travelled with the monk and defended him against demons who were trying to stop his mission.
So pretty far from a demonic character I would say.
In Dragonball the Dragonballs were a replacement for the Buddhist texts from the original story. Also even though the dragons are magical, they turned out to be creations of an alien race, not spirits per se.