Besides storing mana, the player's castle also serves as a home base for the player where he cannot be killed and where he can regain health and mana. As the player expands the castle, it spawns additional mana-collecting balloons and armed guards that defend the castle against attacks by enemy wizards. Greater amounts of mana stored in the castle allow the player to cast more powerful spells.
Only his apprentice survived and his goal is to restore the worlds to equilibrium. One wizard hoped to end everything with an all-powerful spell but instead only left the worlds shattered. The battling wizards began using more destructive spells and summoning deadly monsters, the latter of which often turned against them. Worse, many corrupt wizards began turning to mana for their own nefarious purposes, eventually leading to war between them.
According to this back story, mana was discovered and though it initially had beneficial uses, the quest for it made the lands barren. The story is told in a cutscene that depicts the pages of a book being flipped. The player plays a wizard (on a magic carpet) flying over water, mountains, and other terrain while destroying monsters and rival wizards (which are controlled by the computer) and collecting " mana" which is gathered by hot air balloons and stored in the player's own castle.