Konfrontacja Sztuk Walki better known by its initials KSW, is widely considered to be the premiere mixed martial arts organization in Poland and one of the leading in Europe.

Marcin Held is a Polish mixed martial artist who competes in the Lightweight division of Konfrontacja Sztuk Walki (KSW). He is currently ranked #7 in the KSW Lightweight rankings. He formerly competed in the Lightweight division of the Absolute Championship Berkut, Professional Fighters League, and Ultimate Fighting Championship. A professional MMA competitor since 2008, Held has competed frequently in his home country of Poland and is highly touted by the media, often being regarded as "the prodigy of Polish MMA". He fought in Bellator MMA from 2010 to 2016, challenging for the Bellator Lightweight Championship in 2015.