Dungeon Explorer (1989)

Dungeon Explorer (ダンジョンエクスプローラー, Danjon Ekusupurōrā) is an action role-playing game released for the PC Engine/TurboGrafx-16 in 1989. It centered on the quest of several heroes to find the Ora Stone for the former king of Oddesia. When the alien race that now rules the land invaded, the stone was hidden deep in the dungeons of the land by the King to keep it safe. Now, however, the king wants the players to recover the stone, which can bring life, light, and happiness, and to kill the alien king, Natas: King Satan. The heroes progress through several different dungeons and fight fearsome bosses such as Bullbeast and Grimrose, and finally recover the Ora stone. Upon giving it to the king, however, the king reveals himself as Natas and steals the stone. Additionally, a guard named Judas also betrays the heroes, but is defeated by them. The adventurers then chase and confront Natas, killing him and taking back the Ora stone and ushering in a time of peace.