Grendel: Warchild (1992)

Ten-year-old Jupiter Niklos Assante, heir to the throne of the Grendel-Khan, is stolen from the retreat in which his rapacious stepmother has hidden him away from the rightful reins of power. The child is worth a hefty ransom, but there seems to be more than money on the mind of his kidnapper -- who is none other than Grendel!