Dartz

Dartz is the main villain in the Orichalcos Doom (or Doma) story arc of Yu-Gi-Oh!, a Japanese anime.

Plotline
Dartz is a mysterious figure from Atlantis, who has been corrupted by the power of the Orichalcos. He seals the stone tablet in Domino Museum when Yugi and Atem atempt to regain the Pharaoh's Lost Memories, causing a portal to be created between the Duel Monsters World and our world.

The Doom Organization
Dartz is head of a gang of Duel Monsters players who seek to revive the Great Leviathon from its slumber and conquer the world, returning it to the way that they believe it once was.

They also believe that 10,000 years ago, a rock called the Orichalcos Stone appeared on Earth, and judged mankind as good or evil. They all carry a small fragment of this stone, which can be used to break the Seal of Orichalcos from outside in case of emergency. Supposèdly, the majority of mankind was judged to be evil, and the good and the bad waged war until the good were defeated.

Deck
Dartz plays an Orichalcos deck: a deck that focuses on making an opponent lose life points and make all their moves useless, while increasing one's own life points. Accordingly, Dartz plays Seal of Orichalcos along with Orichalcos Kyutora. Apparently, Orichalcos Kyutora cannot be attacked, and its special ability prevents a player from receiving any battle damage. Dartz uses Orichalcos Gil-Gars, which can return from the graveyard as a result of battle 500 points stronger. Dartz continues to destroy Orichalcos Gil-Gars, and it returns 500 points stronger, and then another 500 points stronger by the effect of the Seal of Orichalcos. Dartz receives no damage because of Orichalcos Kyutora.

Then, Dartz plays Orichalcos Deuterosu. That allows Dartz to gain 500 life points for every monster on his side of the field. Dartz plays four mirror knights along with a mirror shield that prevents the mirror knights from being destroyed. Kaiba was able to destroy the mirror shields and use a special magic card that allows Yugi's Dragon Master Knight to directly attack Dartz, but Dartz sacrifices Orichalcos Gil-Gars to negate that attack. Two turns later, after Kaiba was able to destroy 3 of the 4 shields that the mirror knight had, Dartz plays Orichalcos Toritosu. Dartz then plays Orichalcos Diablos, and Kaiba finds out that trap cards affecting Dartz's monsters are rendered useless as a result of Orichalcos Toritosu.

Later, Kaiba gets the Legendary Dragon Critias, and fuses it with Yugi's Mirror Force to make mirror force dragon. Kaiba attacks the last mirror knight with the shield, the attack is reflected back at Kaiba, and then Kaiba uses special ability of Mirror Force Dragon to counterattack all of Dartz's monsters with the mirror knight's attack of 500. Since all of Dartz's monsters have 500 attack points, they are all destroyed. But that is not meant to be.

Dartz evolves Orichalcos Kyutora into Orichalcos Shinoras, which can summon its left arm and right arm. The left arm and right arm are always 300 attack points more than the opponent's monster attacking it, and they are always designated as first targets. Orichalcos Shinoras has attack points beginning with Dartz's life points (20,000) and loses attack points as it attacks other monsters.

Yugi had only one thing left that can turn the duel around. It was the blank card Pegasus gave him in the Pot of Greed. Yugi didn't put it into his deck, but it magically got there and transformed into the magic card Legend of Heart. It allows Yugi to summon specially the legendary dragons Tamaeus, Critias, and Helmos, then transform them into their true forms: the three legendary knights.

Three Legendary Knights
 * When all three are on the field, destroy Seal of Orichalcos, Orichalcos Deuterosu, and Orichalcos Toritosu.
 * Legendary Knight Critias can automatically destroy all of a player's monsters when it is summonned.
 * You can remove three monsters from your graveyard. Legendary Knight Helmos's attack points equal three times the monster it is attacking.
 * Legendary Knight Tamaeus can fuse any number of monsters together

However, when Orichalcos Shinoras is destroyed, Dartz summons God of Serpent with infinite attack power. Dartz must sacrifice all his life points, but he can’t lose unless God of Serpent is destroyed. Dartz attacks Yugi’s Tamaeus, but Yugi plays his own magic card that summons specially a monster from his hand and he cannot lose until that monster is destroyed. Yugi summons Dark Magician Girl. Yugi then revives Tamaeus. Next turn, Dartz discards ten cards from his deck to his graveyard to allow God of Serpent to have infinite attack. He attacks Dark Magician Girl, but Celtic Guardian somehow comes out to protect her. Then, Yugi orders Helmos and Critias to attack God of Serpent. Yugi plays Attack Transferal Barrier to transfer God of Serpent’s attack on Critias to Helmos. Yugi removes the three magnet warriors in his graveyard to activate Helmos’s ability: it’s attack is equal to three times the monster it is attacking. Then, Yugi uses Tamaeus’s ability to fuse the three Legendary Knights into United Dragon Divine Tamaeus with triple infinite attack. God of Serpent is destroyed, and Dartz loses. (But the real action is further along.)