Millennium Items
Millennium Puzzle
In addition to holding the soul/spirit of Pharaoh Atem himself, the Puzzle is able to fulfill one single wish of the person who had solved it and heighten its owner's chance of success in a game, judging by their skill-level as well as the importance of the game at hand. The hieroglyphs inscribed on the puzzle say, "The one who solves me shall gain the powers and knowledge of darkness..." Its main power grants the owner the powers and knowledge of darkness and shadows, giving him incredible skill at strategy and allowing him to use ancient and powerful magic. That magic is mainly used to start and control Shadow Games. The Millennium Puzzle is the strongest and most powerful of all the Millennium Items.When Yugi activates its magic, the Eye of Widget glows on his forehead. Its most well-known power is Yugi switching his body and mind with the spirit of the Pharaoh.
Millennium Ring
Its primary power is to guide the owner to whatever he seeks, including other Millennium Items, like a compass. It even detects non-physical objects like mystical energies or dark emotions. Like the Millennium Puzzle, it had a soul sealed inside of it, in this case a fragment of the soul of Zorc Necrophades (who had also lost his memories) and a portion of Bakura's past life, Bandit King Bakura. Another well-known power of the Ring is its ability to seal one's soul, or portions of one's soul into other objects, including itself and other Millennium Items. It can also harness the magic of the Shadow Games. It can initiate mystical games where the players cannot be disturbed, cast illusions, and manipulate souls. It also gives the owner other magic powers, including clairvoyance, interfering with the powers of other Millennium Items, immobilizing people, and knocking people unconscious.
Millennium Eye
The Millennium Eye's primary ability is to peer into the mind of an opponent, which allows the owner to know what they're thinking at all times, no matter what. When Dueling, the owner can use the Eye to see their opponent's cards and strategies clearly, giving them a significant advantage. They can also see their hidden memories and sense if there is a spirit inhabiting their minds. Like the rest of the Millennium Items, it can also initiate Shadow Games, materialize the effects of Duel Monsters cards, and also cast illusions and protect its owner from harm among other magical powers. It can also initiate the Mind Card Penalty Game, where it seals the soul of someone inside a card, or in the manga, other types of Penalty Game, as Pegasus used a fatal one on Keith for cheating. Other lesser powers include sensing the location of people of interest.
Millennium Rod
This item's unique ability grants the holder the power to control people's minds, turning them into the owner's mind slaves. By extension, it is also capable of mind manipulation, allowing the owner to telepathically communicate with others, look into their memories, trick their minds into believing what the Rod's owner wants them to, even knock people unconscious, and leave a portion of the owner's mind in the people that he has controlled, like with Bakura Ryou and Tea Gardner. Its mind control power has no effect on one who holds a Millennium Item or someone who has a powerful connection to the ancient games that were played in Egypt long ago, like Yugi Muto, Yami Bakura, Seto Kaiba, or Ishizu Ishtar before she gave her item to Yugi. Also, if the victim has an enormous force of will, the spell can be broken. Like the other Millennium Items, its power over the Shadow Games allows it to materialize and command Duel Monsters and their effects, and cast a Penalty Game against the loser. Marik's games created through this item have been the most brutal and damaging, from memory destruction to pain-inducing.
Millennium Key
Its primary unique ability is the power to unlock the doors of a person's soul, giving the user access to the "Room of the Soul," where their thoughts can be observed, or the "room" can even be "redecorated", allowing the user to alter a person's personality. The brainwashing process can be undone, when the victim touches the Key. Also, the controller can manipulate and destroy the personality. Additionally, in the anime, it grants the user various other abilities, such as the power of invisibility as well as the capacity to sense disruptions among of the Millennium Items, such as the transfer of an item from one owner to another. The Millennium Key also allows the user to communicate telepathically; one such example being the projection of visions into the minds of others.
Millennium Necklace
When first introducing herself to Kaiba and showing him the stone tablet brought from Egypt, Ishizu uses the Millennium Necklace to let Kaiba see a glimpse into the past, particularly over the battle between the pharaoh and a sorcerer that was once the pharaoh's friend. Using it to foresee her victory against Seto Kaiba in the Battle City tournament, Ishizu eventually handed the necklace over to Yugi when her vision failed to come true (which was partly due to the Millennium Rod giving Kaiba a vision that convinced him to change his strategy), knowing that the necklace would be needed for Yugi to defeat and release her brother from the growing evil inside him. After Joey became critically injured after his Duel with Yami Marik, the necklace showed Yugi a vision of him and Joey Dueling, giving him the courage to fight on.
Millennium Scale
The scale's power is the ability weigh a person's sin against the Feather. If a person lies while being interrogated by the owner of the scale, or is revealed to be truly evil, the side opposite of the feather will lower, as if weighted down by the person's sins, and if the side without the feather drops to the bottom, the person's soul will be eaten by Amit, causing death. By placing the scale close to the heart of a person, if the scale tilts, then the person is noted to have darkness in his heart. The Scale has its limits regarding individuals with a extremely evil hearts; Bandit King Bakura was so evil that the Scale fluctuated when Karim tried to weigh his evil, while the absorbed heart of Tragedy turned the white "Winged Kuriboh" dark.
Millennium Stone
While the Millennium Items were being created by Aknadin by sacrificing 99 humans from Kul Elna, he put the blood, bone, and flesh in the Millennium Stone in order to forge them, with all slots for each of the Millennium Items the exact same shape and size as them. In the manga, during Pharaoh Akhenamkhanen's reign, the Pharaoh sacrificed part of his spirit to seal a soul within the Stone. That spirit was Hasan, guardian of the Pharaoh.
The Stone was in Kul Elna in the Shrine of the Millennium Stone, and was used by Bakura to put the Items in the Stone in order to summon Zorc Necrophades. When he stole the Millennium Pendant and the Ring, he inserted them in the Stone. Later, during Atem's, the Priests', and Bakura's fight, Mahado attempted to destroy by making a pillar fall on it, so that "Diabound" can expose itself by protecting it. However, it failed when Bakura Summoned "Skeleton Fiend" to protect it. In the anime only, Bakura seemed to have merged with the tablet. Then Zorc emerged, thus destroying the Stone in the process. In the present, when Marik, Ishizu, Yugi and co. went to the shrine for performing the Ceremonial Battle, Yami inserted the Items into the Stone. Later, after the Battle, the palace started to fall apart, and the Millennium Stone shattered.