The Crystal is a large gemstone with strange markings of unknown origin. It presumably has the ability to harness and store enormous amounts of magic power. Besides having to save the four princesses, retrieving the crystal is the other main objective of the game.
At the start of the game, after successfully storming into the King's castle with an army of barbarians and slaughtering most of the King's forces, the Evil Wizard approaches him and, with a couple of swings of his magic wand, releases the crystal from behind the King's throne, then he climbs on top of it and escapes from the castle, sparing the King's life as he decides he doesn't present a threat now that he has the crystal in his hands.
The crystal is seen once more at the end of the Industrial Castle. After destroying the Industrial Machine, the Industrial Prince will grab the Orange Princess, run to the castle's balcony and get cornered there by the King's knights. The Evil Wizard will suddenly appear riding the crystal and take the princess away, abandoning the Industrial Prince to his fate.
Not much is known about the crystal's powers, but considering that it is worth to start a war only to obtain it, and without regards of how many lives are lost for this purpose, one can just assume that those who possess it will be granted an incredible amount of power. However taking the final boss' difficulty into consideration, this so-called "incredible power" is certainly not related to physical strength or magic power.
One can also assume that many of the Evil Wizard's magic powers and abilities were incremented as soon as he got his hands on the crystal, to the point of being able to make his castle float through the air, and also to be able to transform himself into a giant spider or call meteors from the sky.
- In the Wizard Castle Interior, the King's knights have to destroy three purple crystal-like formations, each guarded by one of the Evil Wizard's loyal servants: the Painter, the Undead Cyclops (with the Undead Groom), and the Necromancer. Destroying each one of these crystals will remove a magic barrier and allow access to the next boss fight.
- Starting from Wizard Castle Takeoff and throughout all of the Wizard Castle Interior, many similar crystals can be found scattered in the background. Some of them have skeletons of unfortunate victims embedded in them. Even the main facade of the Evil Wizard's castle is decorated with many crystal-like motifs, which could make one speculate if the whole castle was made from magical crystals.
- The various green crystals one can find scattered throughout the last three levels can also make one speculate if they are disposed magic crystals from which the Evil Wizard has already depleted their magic powers.
- The King's crystal seems to be the only one which has markings all over it.
- It seems that the crystal has also the ability to reflect what's in the heart of its possessor. It will glow fiery-red if he has evil intentions, or turn white and calm if he uses it for good.