Timeline

Pre-Universe

 * At the beginning of the universe, only Nothing exists.
 * Nothing experiences agonizing loneliness, and decides to create something to share the universe with it.
 * Nothing creates Light and Darkness.
 * Nothing perishes, as it can not exist in a world with Something, however, as it dies, it makes a wish for nothing in the universe to ever feel the loneliness that it had felt. From that wish is born a heart that exists between the Light and the Darkness.

Creation of the Universe

 * The three forces left behind by Nothing grow into sentience over a vast amount of time, taking on the forms of the first dragons.
 * The Heart develops into the Numeron Dragon, and the Numeron Dragon leads Light and Darkness in the creation of the universe.
 * The Numeron Dragon eventually passes on after the majority of the universe and its twelve dimensions have been created. The Dragon splits into three parts: Soul, Heart, and Body, each of which nestles into various corners of the universe. The Soul develops into the Crimson Dragon, the Heart into the Numeron Code, and the Body into The Door.
 * The union of Light and Darkness gives birth to the first generation of deities.
 * Humanity and the Shadow People are created, and due to the wish of Nothing, humans and Shadow People are born in connected soul pairs.
 * Humans and Shadow People begin to live alongside each other across many of the first habitable dimensions, and develop civilizations, living alongside the gods that created them.

The First War of Existence

 * One of the gods, Apep, a god of destruction, grows resentful of humans and Shadow People. Desiring to create a world of only deities, Apep breaks the laws of the universe by performing an act of creation, creating the demon Red Nova.
 * Red Nova's creation creates a tear in the universe that resolves into Aberrations, including Armityle, and also creates both the Light of Destruction and the Warped Darkness.
 * The rest of the deities struggle to fight back against Apep and its armies, causing Light and Darkness to sacrifice themselves and become a new power, which they gift to a willing human host who becomes the first King of Light and Darkness.
 * The King of Light and Darkness beats back Apep and strips it of its power, flinging the last of its consciousness across the universe.
 * The King of Light and Darkness unites the twelve dimensions, and vows to protect it and keep its balance forevermore.
 * Red Nova and Armityle go into hiding.

The Second War of Existence

 * The remnants of the Light of Destruction and the Warped Darkness continue to cause problems for unified humans and Shadow People.
 * Armityle convinces several Shadow People, using the Light of Destruction, to kill their soul-connected humans, causing a new imbalance.
 * The second King of Light and Darkness defeats Armityle and splits them into three parts. Horahkty, the god of light and justice, requests to be split as well, in order to fill the imbalance caused by Apep's removal. She becomes Obelisk, Slifer, and Ra.
 * The King of Light and Darkness seals away the corruption of the Light of Destruction. The Warped Darkness continues to run wild, and the King falls prey to it.

The First War of Distortions

 * Distortions left in reality from the previous wars between deities create the Aberration known as Don Thousand.
 * Don Thousand attempts to gain control of the Numeron Code. Humans learn how to Rank Up their souls in order to escape to another, higher dimension, in order to keep the Code safe.
 * The current King of Light and Darkness pushes Don Thousand back, but in the struggle is forced to cast a spell that will separate humans and Shadow People. From this point forward, humans will only be born in the Physical Realm, and Shadow People will not be able to manifest there without energy.

The Second War of Distortions

 * Don Thousand rises once more, and chases the Numeron Code into Astravaria, where the Ranked Up humans fled.
 * The Astravarians create the Astral Project to defeat Don Thousand.
 * After the continued failure of the Astral Project, the Barian Protocol is initiated, causing Astravarians to turn against each other.
 * Astravaria splits into two separate worlds, Astral World and Barian World.
 * The final Astral Project homunculus, Astral-99, is able to push back Don Thousand, but immediately goes into dormancy after.

The First Signer War

 * Red Nova comes out of hiding and creates the Earthbound Immortals.
 * Upon the siege of humanity by the Earthbound Immortals, the Crimson Dragon reawakens and imprints itself onto human souls.
 * The Signers are formed, and seal the Immortals and Red Nova away.

3000 B.C.E.

 * Atem is born.
 * Apep is reawakened using the power of the Millennium Items, and nearly lays waste to humanity.
 * Atem sacrifices himself in order to seal away Apep.

April

 * Yugi solves the Millennium Puzzle and reawakens Atem.

May

 * Shadi reveals himself and the rest of the Millennium Items to Yugi and Atem.

June

 * Kaiba lures Yugi and his friends into Death-T.

October

 * Ryo Bakura transfers to Domino High School.

March

 * Duelist Kingdom occurs.

April

 * Battle City occurs.

September

 * Yako Tenma uses the Wicked Gods to attempt to resurrect Pegasus.

December

 * When The Lotus Blooms

March

 * Yami no Jigsaw

April

 * The Knights of Orichalchos arrive to challenge Atem and Yugi.
 * The KC Grand Prix takes place.
 * What Lies Within [Yugi's Timeline]

May

 * Battle City II takes place.
 * Judai arrives from the future to duel Yugi and Atem.

June

 * Judai and Yusei arrive in the past in order to help Yugi stop Paradox from destroying Duel Monsters.
 * Yugi and friends go into Atem's memories to regain his name.
 * Yugi and Atem have a final duel, and Atem returns to the afterlife.

March

 * The Plana attempt to stop Kaiba from resurrecting Atem.

April

 * Yugi and friends graduate from high school.

2008 C.E.

 * Judai and friends begin attending Duel Academia.
 * The Seven Stars Assassins attempt to steal the Sacred Beasts.

2009 C.E.

 * Saiou Takuma, possessed by the Light of Destruction, attempts to destroy the world.

2010 C.E.

 * Yubel is brought to Duel Academia by Professor Cobra.
 * Duel Academia is dragged into another dimension for a period of time.
 * Judai and friends return to the other dimensions to retrieve Johan.
 * Judai succumbs to his past life as the Supreme King for a period of time.
 * Dark Matter
 * The Warped Darkness rises once again and tries to steal the souls of all humanity within its pocket dimension.
 * Judai and friends graduate from Duel Academia. Judai goes to the past in order to duel Yugi and Atem.
 * What Lies Within [Judai's Timeline]

2023 C.E.

 * Judai and Johan reopen the Osiris Dorm as a special dorm for powered kids.

2025 C.E.

 * Red Days
 * Saki and friends begin school at Duel Academia in the Osiris Dorm.

2026 C.E.

 * Osiris Blues
 * Armityle attempts to resurrect again by trapping souls inside of pocket dimensions, but is foiled by Saki and her friends.

2027 C.E.

 * Duel Spectrum
 * Saki and friends graduate from Duel Academia.

2034 C.E.

 * The Zero Reverse accident occurs in Domino City.

2052 C.E.

 * Yusei gathers the Signers to defeat the Earthbound Immortals.

2053 C.E.

 * Yusei and friends join the WRGP, and eventually face off against the Meklords.
 * What Lies Within [Yusei's Timeline]
 * The Callisto Project

2081 C.E.

 * Yuma meets Astral for the first time.
 * What Lies Within [Yuma's Timeline]

2082 C.E.

 * The Barians begin their assault on Earth.
 * The Only Thing That Matters
 * In the Quiet

2130 C.E.

 * Ray and Zarc clash, causing the Physical Realm to split into four separate pocket worlds.

2144 C.E.

 * The Dimensional War begins.
 * What Lies Within [Yuya's Timeline]
 * The Things We Hide
 * Through the efforts of Yuya and others, the four Physical Worlds are reconnected, and Zarc's restless soul is soothed.

2145 C.E.

 * The Greatest Show On Earth...and Elsewhere