For currently unknown reasons, powerful energies gathered together, and in a great burst, completely altered reality. It did so by merging four distinct and different time periods into one new time period that had elements of each of the four. The four time periods that had been combined were none other than four important times for Duel Monsters, and they were the era of Yugi Muto, the era of Jaden Yuki, the era of Yusei Fudo, the era of Yuma Tsukumo, and the era Yuya Sakaki.
In this new reality, the city was called New Domino Heartland City, and it took elements from Domino City, New Domino City, Heartland City, and Maiami City from Yugi, Yusei, Yuma, and Yuya's cities. It also had some of the elements of Duel Academy Island surrounding it like the forests and the the volcano, and connected by bridge was Satellite. The city was a popular destination for Duelists from around the world due to its Pro dueling arenas, and its highways for Turbo Dueling. Notable foreign duelists included Rebecca Hawkins from America, Sherry Leblanc from France, Vivian Wong from China, Greiger from Peru, Team Unicorn from Spain, and Team Ragnarok. Occasionally, a Duel Monster from the Spirit world might even visit from their world. One notable monster was the Dark Magician Girl.
Yugi still attended Domino High School with his friends like Tea, Joey, and the others. Yugi still had the Millenium Puzzle, and the spirit within it still had yet to regain its memories. Kaiba also attended like in the original time period, and was still the head of KaibaCorp. Mai lived here on her own. Ishizu also worked at the museum. And Kisara from ancient Egypt had been reincarnated in this new time.
Like in Yuya's time, their were many Duel schools in the city, including Jaden's Duel Academy. The grounds of the Academy was on the edge of town, and it had all the dorms of the other, and now it also had the new Junior dorm. Jaden and friends were in their first year but Jaden still had Yubel, Blair and Hassleberry were students with them, and Jesse, Aster, Axel, Jim, Adrian, Reggie MacKenzie, and David Rabb were visiting transfer students from different Academies. Zane, Atticus, and Seika were each in the final year. Along with the original, the Duel Academy that Akiza, the twins, and their friends attended was also present, as well as Yuya's You Show Duel School and thte Leo Duel School, and many others
Yusei, Jack, and Crow had their garage. But Rex was also still head of Sector Security, and Kalin, Carly, and Misty weren't Dark Signers.
Yuma and his friends all attended their Middle School. Yuma still had Astral, and still working on collecting the Numbers. Dr. Faker was also the head and founder of Heartland, his deal with Barian not in effect anymore in this new time either.
As for corporations, Reiji's Leo Corporation rivaled that of Kaiba Corp.
Jaden's Duel Academy, Yugi's High School, Akiza's Duel Academy Yuma's Middle School, and Yuya's You Show Duel School were all close to one another. And of course, Yugi, Jaden, Yusei, Yuma, Yuya, and their friends knew each other, and were friends themselves. Yugi, Jaden, Yusei, Yuma, and Yuya were all close, each having won tournaments like Duelist Kingdom, the Fortune Cup, and the WDC. Astral and the spirit of the Puzzle had a bit of a friendship, being able to relate to one another's situation. Tea was close friends with Alexis and her friends, Akiza, Tori, and some of the other girls. Yugi could also see spirits like Jaden, Jesse, Chazz, and Luna, and his Kuriboh was friends with Jaden's Winged Kuriboh and Luna's Kuribon.
And no one knew that this new, fused time period was any different. As far as everyone knew, things had always been like this.
Of course, the power that had caused this wasn't finished, and it was going to cause something else to happen. Now, what will happen?
The Mysterious Spell Card "Gender Swap": A strange card is found, and it can cause male and female characters to change into the opposite gender. Can happen instantly or gradually.
The Mischief of the Swap Frog: Inspired by the Journey of the Swap Frog by Stardust. A Swap Frog card with a spirit obtains the power to swap things, and uses it to have some fun with the characters.
The Mysterious Spell Card "Life Swap": Through strange cards found, various different characters swap lives with each other. People find the card, and are life swapped with someone else who found the card.
Duelist Monsters: A mysterious energy energizes certain cards important to people for unknown reasons, causing the owners of the cards and/or those close to them to gain traits of those cards. Examples include Yugi and Tea gaining the powers and clothes of the Dark Magician and Dark Magician Girl, and the Signers gain powers and clothes related to their dragons.
Or it could be a bit scrambled and make it so that people get other cards based on the opposite gender
*Note 1:One or the other happens based on the first for it to happen to, for example, if Yugi and Tea find gain the Dark Magicians of their gender, then everyone gets their own or close to it, so Jaden would get Neos, . But if Yugi ended up as Dark Magician Girl, everyone gets opposite gender based, like Jaden gets Alexis's Cyber Prima, and Yusei as Akiza's Black Rose Dragon.
**Note 2: Also, for the first time, you can leave an option for physical changes like gender to take place or not. After that, all following choices follow that option.