Balrog, known as M. Bison or Mike Bison in Japan, is a character from the Street Fighter series.
When Street Fighter II was localized in English, Capcom was afraid of a lawsuit from Mike Tyson over the character's obvious allusions to him and his similar name. They decided to switch around the names of the three bosses: Balrog became Vega, M. Bison became Balrog, and Vega became M. Bison. In certain illustrations, "Bison" can be seen on the waistband of Balrog's trunks, although it's usually removed when these illustrations are published outside Japan.
Balrog was once a great boxing champion and prize fighter. He was banned from boxing for severely injuring his opponents, killing one of them (as well as his illegal maneuvers, particularly his headbutt). He ended up joining the Shadaloo criminal organization and worked his way up from the bottom, eventually becoming Bison's enforcer. While running errands for M. Bison (Vega in Japan), he killed Dhalsim's elephant with a single Gigaton Punch.
When M. Bison was killed at the hands of Akuma, ownership of Shadaloo was transferred to Balrog, who promptly let it fall to ruin and lost all of his influence.
In Street Fighter II: The Animated Movie, he is portrayed close to his original role in the games, which is largely as dumb-muscle for Bison. He is voiced by Joe Romersa in the English dub and George Nakata in the Japanese version.
In the 1994 live action film, he was portrayed by Grand L. Bush and recast as a protagonist, acting as the camera-man in Chun-Li's news-crew. Like the other members (Chun-Li and Honda), Balrog held a grudge against Shadaloo for ruining his boxing career. Near the end of the film, he dons his regular outfit from the games. In the 1995 animated series, Street Fighter, he is a scientist for Bison, with his storyline intact. He is voiced by Paul Dobson.
Balrog's alternate costume from Street Fighter 4:
Balrog's alternate costume from Super Street Fighter 4: