The underdog duelist that wants to be known for something.
This guy was pretty much the hero in his old town, but now that he realizes there is a bigger world out there he wants everyone to know his name. He is not afraid of anything unless it actually starts inflicting pain onto himself. He is also very protective of any of his close friends, and he wants to destroy all evil in the world. Mostly people think of him as a hero.
Just his deck and the clothes on his back.
Like we have established before he was a smaltown hero ever since he was born from the mayor's wife. He had a standard childhood in the 3rd class of rich people meaning they weren't very rich. As Yuu grew up he began fighting off crime from the town pretty much saving it multiple times.