One of the greatest videogame character rivalries of all time has to be the one between Ryu and Sagat in Street Fighter. Ryu represents the martial arts style of Karate, and Sagat practices Muay Thai. Their rivalry made for great story telling in the videogames, as well as the comic books and animated films that came later.
Ryu and Sagats fictional rivalry was based on the real rivalries between Japanese karate-ka and the Thai boxers they fought when they were developing Kyokushin karate.
You can witness what it might be like if Ryu and Sagat fought in real life in this great match up between Hiroki Akimoto (Kyokushin Karate) and Capitan Petchyindee (Muay Thai).