The young swordsman Raru sets out on a quest to become a hero after hearing tales of his legendary name. On his journey, he stops at an inn in the town of Hyuma, where a sudden commotion erupts upon waking. The town is now surrounded by walls, and the only way out is through an underground passage.
Deep Dungeon III is a first-person RPG that marks the debut of the four-member party feature in the Deep Dungeon series . The player can choose one of three characters - ranger, magician, or priest - to accompany Raru on his quest. However, these companions are vulnerable to death and must be replaced if new ones are encountered during exploration. If Raru falls in combat, the game is over.
The game begins in the town of Hyuma, where the player explores to find a passage to the underground world, visiting shops along the way. The gameplay builds upon mechanics introduced in Deep Dungeon II , allowing players to distribute points among character stats during leveling-up and reducing random battles when a character's level exceeds that of the monsters on a given floor.
The game features multiple dungeons for exploration, offering a more extensive experience compared to previous installments.