Dungeons and Dragons (1983)

While taking a lesuirely ride through the forest, Dungeon Master is attacked by a Warduke, a bounty hunter who possesses a sword that covers that which it is struck against with ice. He strikes the side of the tree Dungeon Master is perched on, trapping Dungeon Master in a block of ice. When the kids are made aware of Dungeon Master's capture, they set out to rescue him before Venger can claim him first.