Welcome to the power of darkness!
The Dark King is the primary antagonist of Final Fantasy Mystic Quest. A green-skinned monarch in regal robes, he watches over the world from his throne in Doom Castle, situated above the Focus Tower.
The Dark King initially appears as massive, green-skinned man wearing a red, white fur-trimmed robe with a gold rope fastener. In the Japanese version, the "rope" is a thread of jewels with tufts of fur at the end. He wears purple robes with white linings, and a gold crown. He holds a gold and silver scepter with a red orb on top (in the Japanese version, the scepter is curved and has a cobra head-like mounting and a skull). He has blank white eyes (red in the Japanese artwork). Although not present in either the in-game sprite or the European artwork, his Japanese artwork depicts him with tufts of white hair and a purple belt with gold linings and three red jewels, and with long fingernails.
His crown has some differences between the versions: in the Japanese artwork, the Dark King's crown is gold with a red fabric top and gold lines and multi-colored jewels. It resembles to the Georgian Crown as worn by King George XII. The European artwork depicts it as having at least four square ridges, a central red jewel and multiple jewels of differing colors on the sides. The in-game sprite is similar to the latter, although it has three red jewels and three ridges. Similarly, his face in the sprite and European artwork depict him with a thick imposing face, while in the Japanese artwork his is more gaunt.
Upon first transforming, the Dark King gains two additional pairs of arms, each with white hands with two fingers and a thumb (with the exception of his upper right hand, which still has green skin). He ditches the scepter, instead wielding several weapons: he holds a battle axe on his lower right arm, a rapier on his middle left arm, a longsword with a golden handle and a red jewel in the center on his upper right arm, a katana on his upper left arm, a cutlass sword on his middle left arm, and a bow and arrow on his lower left arm. His robe is sprawled open, revealing his purple robes in full as well as a gold wheel-like ornament on his chest. His face becomes more demonic, showing two large white pincers coming out of his mouth, and gaining two white horns.
He then transforms into a spider where he has a green face, serrated pincers at his mouth, four fangs, curved white horns, two large white eyes, and six smaller white eyes and antenna. His body becomes gold, gray and red and resembles a tarantula with red markings on his abdomen. He has primarily yellow legs and red tips, and white hairs near the tips of each leg. He implies this is his true form.
The Dark King's final form is similar to the third form with red eyes. Most of the hairs have turned green as well as the antennae, and his legs have been reduced to writhing red tentacles, with two of them partially amputated.
The Dark King is arrogant, as evidenced by his taunt before transforming the first time where he thinks Benjamin and Phoebe's actions against him are amusing. He asks if that is all they can muster. Before fighting Benjamin and Phoebe, he insists that they now serve him. Upon transforming the third time, he growls, indicating he is starting to lose his cool.
The Dark King is the secret master of the Vile Four, and the one who ordered them to drain the Crystals of their power and weaken the land. The Crystal of Light shines at the Dark King's throne when he is killed. The significance of this is not explained, though it may imply the Dark King was draining its power as the Vile Four were draining their respective Crystals.
Centuries ago, the Dark King started a rumor that would become known as the prophecy that foretold of a Knight who would arise to defeat the Vile Four and kill the Dark King. Though it is not explained why the Dark King started this rumor, the Crystal of Light believed it to be true, and believes Benjamin is the Knight it predicts will defeat the Dark King. With the Crystal of Light's guidance, Benjamin saves the Crystals and climbs both the Focus Tower and Doom Castle to confront the Dark King. With Phoebe's help, he defeats him and saves the world.
The Dark King is fought at Doom Castle's summit as the final boss.
- In his second form, the Dark King takes on the appearance of a six-armed man wielding six weapons, and bears a slight similarity to Gilgamesh. The Gilgamesh of mythology was also once the King of Uruk and became a dark character who quested for immortality.
- The Dark King is the only enemy/boss character in the game who actually transforms into his various phases, instead of merely having his battle sprite being altered to indicate his current status.
- The Dark King's true form being a spider may have been a reference to the titular main antagonist from Steven King's It.