Yugi Mutou/Pharaoh Atem, Judai/Jaden Yuki, Yusei Fudo, Yuma Tsukumo and Yuya Sakaki. What do all these top duelists have in common?
Firstly, all their names have "Yu" in them, all in their first names except for Judai/Jaden, who's surname instead carries the "Yu" legacy. Secondly, all their prized monsters share the same attack power of 2500 (Yugi/Atem - Dark Magician|Judai/Jaden - Elemental Hero Neos|Yusei - Stardust Dragon|Yuma - Number 39: Utopia|Yuya - Odd Eyes Pendulum Dragon). Thirdly, their rivals thought them to be weak and lack any skill to duel.
Their summoning techniques consist of Yugi/Atem and Judai/Jaden using Fusion summoning, and quite recently, so has Yuya. Yusei is the master duelist of the Synchro summon, whilst Yuma has the profession to XYZ (Exceed) summon.
But what inspired them to reach their goal?
Yugi/Atem (Duel Monsters) sought to retrieve Solomon's (Grandpa's) soul from Pegasus during the Duelist Kingdom tournament, becoming the King of Games, upon defeating Pegasus. Due to his role, he has had to face many tough challenges, not only to change the fate of the world multiple times, but also to keep his title until he was willing to give up his title.
Judai/Jaden (GX) was a young teenager with a troubled past who dueled for fun. This was until the world started to darken with evil plans from many who opposed him, like Kagemaru, Sartorius, Yubel and Viper, he battled each of them and reigned victorious over each of them, along the way becoming the evil Supreme King in the Dimension world. Fusing with Yubel at the end of season 3, he felt as if he needed to improve himself as a person, as well as a duelist, journeying as far and wide as he could.
Yusei (5D's) was an orphan due to the Zero Reverse disaster, his father saving Yusei's life by sending him to the Satellite sector via Escape pod chute. He used his quickly obtained knowledge of computers, as well as his engineering to build his own Duel Runner, with the help of his good friends from within the Satellite. He sought revenge on Jack after Jack Atlas' betrayal towards their group of friends, and this lead to him becoming the King of Turbo duels, waging a battle with the Dark Signers and the Yliaster, resulting Yusei's victory against most of them. After all the chaos the Yliaster caused had ceased, Yusei and the other signers were relieved of their marks so they may continue with their lives without the stress of saving their world.
Yuma (Zexal) was a duelist who struggled to win any duel, until he met Astral, who guided him over a mass period of time, helping him conquer the Barian world citizens, who planned to destroy Astral world, as well as the Human world. Astral's life mission was to destroy the Barian world, as well as to collect the Number cards, Number 1: Numeron Gate Ekam to Number 100: Numeron Dragon. Winning all duels since meeting Astral, Yuma still always had wanted his father Kazuma to return home, regardless of where his father had gone, as well as wanting his dream of becoming a professional duelist to come true.
Yuya (Arc V) is a dueltainer, someone who prefers to duel for entertainment rather than dueling for serious conflicts in life. His father had disappeared before an exhibition match that Yuya instead participated in a few years later. The pioneer of Pendulum summoning, he dreams of becoming a pro-duelist master like his dad was, but really just as a dueltainer. Series is still ongoing.
Each of these duelists have their own stories, though some may be similar to another's.
Yugi/Atem, Judai/Jaden and Yusei, all showed up in the film Yu-Gi-Oh! 3D: Bonds Beyond Time, where they combined their dueling skills together and defeated Paradox, a rumored member of the Yliaster. This film was set before the World Grand Prix set in Yusei's time frame, and was the only film thus far to combine more than one protagonist from an ongoing YuGiOh series (Yet to be confirmed).
In the comments below, please let me know which duelist is your favorite and why.