Short answers, pulled from the story.
Sodom is an American Japanophile and the boss of the Subway stage in the game Final Fight. He is a member of the Mad Gear gang who wears a samurai kabuto with a mask, blue jeans, and body armor. He wields two katana swords named Masamune and Muramasa.
Sodom emerged as the boss of the Subway stage in the game Final Fight in 1989. He fought the player in a ring beneath Metro City as an underground wrestling promoter. His defeat in the game marked the beginning of a journey that would see him travel to Japan to re-educate himself.
After being defeated by Guy in Final Fight, Sodom traveled to Japan to re-educate himself. He developed a new fighting style based on Japanese and Western martial arts and traded his swords for a pair of jitte. In his ending, he reformed the gang and held up a poster to signal a new chapter in his life.
In 1993's Mighty Final Fight, there were three Sodoms known as the Three Katana Brothers who fought the player. Each brother had their own unique style and personality yet they all shared the same goal of defeating the player. This expansion of the character's role allowed for a more dynamic and challenging experience for the player.
The name Sodom itself carried heavy biblical connotations that the Japanese developers likely did not intend. The character himself seemed unaware of the word's true meaning in English, creating a disconnect between his appearance and his understanding. This disconnect created a unique archetype that blended the serious with the absurd.