Valkyrie no Bouken : Toki no Kagi Densetsu

Once upon a time, the Marvel Land was a peaceful place populated by humans and other races. Zouna, a dark wizard who had once threatened the land was securely sealed in a clock tower. One day, the clock stopped working for unknown reason, and a villager who tried to fix it inadvertently dropped the key of time. A catastrophe ensued: Zouna broke free and took the key with him, preventing anyone from sealing him again. The dark minions of Zouna corrupted the hearts of Marvel Land inhabitants. Hatred and chaos descended upon the world. Finally, a savior has arrived - Valkyrie, a maiden from heaven vows to save Marvel Land from evil and defeat Zouna.