Babylonian Castle Saga

The player assumes the role of the hero Gilgamesh, whose goal is to rescue the maiden Ki (カイ, Kai) from the demon Druaga. In order to do this, he must traverse through 60 floors of an immense tower. Gilgamesh comes equipped with a sword, which he can use to defeat monsters, and a shield, which can be used to block magical attacks.

It picks up where Tower of Druaga left off. The player controls two characters: Ki as well as Gilgamesh. It can also be noted in this game that Ki is a magician, not a damsel in distress like many people believe. The tower now has a few different ways to exit, and the aggregate total of levels is 128 (covering the 60-floor tower).

The story of The Quest of Ki is actually a prequel to the original Tower of Druaga. It occurs shortly after the demon Druaga has stolen the Blue Crystal Rod and taken it to his tower. The goddess Ishtar sends the priestess Ki to the tower in order to retrieve it. The game then follows her doomed quest to the top of the tower, and leads directly into the story of the original game.

Also known as "The Destiny of Gilgamesh", this game picks up where Return of Ishtar left off and is the final game in the Tower of Druaga series, according to Namco.

This game is set three years after the original Tower of Druaga tetralogy. In it, Ki and Gilgamesh are about to be married, only for Ki to be kidnapped by an evil sorceress, Skulld. The game is known for its unforgiving difficulty, as death in the game results in losing all items and half gold, and its harsh penalty for resetting. Should a player reset the game, they will be greeted by Ishtar, who will scold them for "meddling with the flow of time".

Nightmare was not made by Namco, but by two other companies called Arika and Chunsoft. It was far less successful than the prior games, and was even given a low rating in a video game magazine. This game is the fifth in the "Druaga series" (not counting "Drururuaga"), and the eighth in the aforementioned Mystery Dungeon series.

This game is placed about 100 years after the original Druaga timeline and stars Gilsh, a descendant of Gilgamesh. Gameplay is best described as a dungeon-building capture the flag with collectible cards. The players use cards to equip character with weapons and spells, and to populate dungeon with monsters. Then the players battle against an opponent and his dungeon (AI or link cable). The players enter the opponent's dungeon via linked teleporters, find the three keys to unlock the crystal, and return it to home base before the opponent does the same. Success yields additional cards. Each item or monster is highly specialized, allowing for different strategic combos. It features many Namco cameos, such as Soulcalibur's Nightmare, the sword Soul Edge, Valkyrie, Pac-Man, and even the enemies from Dig Dug.

This game is set outside the main chronology of the series, and borrows characters from Namco's Valkyrie series. Gameplay is similar to The Return of Ishtar, only four players may play at the same time; each controlling one of the four available characters: Gil, a young version of Ki, Valkyrie, or an ancient golem named Xeovalga. Players also earn gold from killing enemies that can be used to upgrade equipment.

This game is an MMORPG developed as part of the Tower of Druaga "Animation x Online RPG" project which also includes the anime series The Tower of Druaga: the Aegis of Uruk.