Souga

The Strategist of Ken-oh's Army and Reina's elder brother. Also known as Souga the Swift Footed (韋駄天のソウガ, Itaden no Sõga), a master of the Songshan Whirlwind Kick (嵩山旋風脚, Sūzan Senpū Kyaku). In the past, he sacrificed his right leg to help Raoh and Reina escape from Cassandra, which was then replaced by a prosthetic. Like Reina, he was originally a character from the 2006 anime film Fist of the North Star: The Legend of Raoh - Chapter of Love in Death.

(Source: Wikipedia)