I got this stuff going through my head after watching a series of Yugioh Crossover videos where the cards are replaced by anime characters (except some of the most important ones like BEWD and Dark Magician) from anime such as S-Cry-Ed, Nanoha, Fate Stay Night, GaoGaiGar, and maybe a few others. And most of the anime characters seem sentient like they are duel spirits. And this triggered a few ideas from it in the form of a dream.

The setting is like this. It takes place in a world where the people have all the same anime that we have. However the characters are spirits that contract human partners whom they choose. When contracted they can become solid tangible beings. Or shift back to spirit form. They cannot engage in battle without it either being in a duel through being summoned by their contract masters through Things called Character cards that can be used as Yu-Gi-Oh monster card (most have effects), or by being given permission from the contract masters. If they do not find a master within three weeks they will either die out or live if they have something that can keep them there like a special item. In this the hero know as Fukami "Ryoma" Kai (he was born as Ryoma but liked kai better). He loves Super Robots and anime as well as Super Sentai and anything mecha related. Here he already has contracted a few and gotten character cards.

The first "episode/chapter" of this idea plays out similarly to episode one of the original Duel Monsters episode except it does not begin at school. It begins as out hero is drinking a beer (he is in college) and we all of a sudden see him talking to a buy at a counter. Guess what? It is our hero Kai who owns the game shop in this one. Well it is more geared towards video games though. He is greeted by a person from school who plays the role of the villain and is joined by his character cards spirit in solid form and it is saber from Fate Stay Night. He challenges him to a duel where the winner gets the losers character cards. Kai refuses. The young punk then comes back and offers him his character cards as a prize and all you can drink and eat at his favorite restaurant. He accepts with a twinkle in his eyes.

The duel (which was mixed with Yugi's first duel with Kaiba and a few twists) begins with the young punk revealing himself as Kenji Karuto. They agree to play by the same rules that use 2000 as life points. He starts the duel off by playing who else other than Kotomine Kirei with 1200 attack. Kai summons (I can't believe this was how it went in my dream) Corticarte Apa Lagranges with 1400 attack. Corticarte is pissed that she got called out like this and ends up blasting the enemy in a comical fit of rage. We then see Kenji summon Caster (the equivalent to sagi the dark clown). Kai wonders why he summoned her in attack position when her attack strength is only 1000 and her defense is 1800.
He then uses a "My Dream Only" magic card called reinforced shield and sword which is a permanent version of shield and sword. Caster attacks with a magic shower of shrapnel like explosive magical blasts. Corticarte is yelling for Kai to do something and all he does is say "It wont hurt much... For me". He loses the battle and gets 400 points of damage.

Kenji proceeds to wipe out more and more monsters with caster until Kai summons WolKentauros from Magiranger with 2300 attack (his equivalent to Gaia). He wins but it is then destroyed by a stolen BEWD. Kai gets pissed saying he wanted to steal it for himself (he is an a**hole). Kai must play a regular monster in defense. It gets destroyed and Kai must defend again but this time Kenji plays *drum roll* Saber!
She quickly annihilates the defense with her attack of 2500. Kai then plays swords of revealing light and freezes his enemies monsters. Kenji plays Beserker (2200) and destroys yet another defense. Kai then resurrects Corticate with revive the dead (Monster Reborn's Japanese title translated directly I believe) and then plays Hero card Phoron (cards containing the main characters of animes and there are different kinds). It summons Phoron who then transforms Corticarte into her adult form with a total of 2500 attack. She destroys berseker. And now Kenji draws and plays a second stolen BEWD free of the swords (the other two are not free yet) and attacks Corticarte reverting her back to her 1400 attack form and Phoron leaves the field (they can only be used once). Nearly beaten, Kai draws his last card and notices the five cards now in his hand. G-Crystal (Non-Monster), Straight Gao & Spiral Gao (one card with 1000 attack that can attack twice), Broken Gao & Protect Gao (same effect and attack as Straight Gao & Spiral Gao), Gadget Gao (attack 1500), and Genesic Galeon. He then proceeds to summon Genesic GaoGaiGar with an attack of 4000. He has him launch the Genesic Bolt and destroys Saber and ends the duel. He then is given the Fate Stay Night character cards that Kenji had managed to contract. They perform a de-ritual to create a new contract with Kai as they must obey the promise of giving the winner their character cards.