In Tao's Adventure: Curse of the Demon Seal, the player controls the young Air Speller by the name of Tao. When his village gets attacked by Ancient Monsters, he is sent by the council over to the town of Mondominio to seek the help of a friend of his father. Mondominio is famous for containing the Monster Tower which was sealed for many years until a lightning storm hit the tower and broke the seal.

The game plays quite similarly to Azure Dreams. Most of it is based around leveling up, learning new spells, and collecting monster eggs from the monster tower, and then selling them in town or hatching them as pets that will aid you in your quest. The player begins with the basic elemental spells which are cast using the DS stylus. The battles, movements, and almost any action taken in the monster tower is turn-based. The higher the player progresses up the tower levels, the stronger the enemies become. With every five levels of the tower, the player will encounter a boss.