United Force is the organized ultras supporters group of the football club FK Rad, based in Belgrade, Serbia. Founded in 1987, this passionate group is well-known for its deep loyalty and distinctive visual identity, which relies heavily on the colors blue, navy, and black. Luka Perenčević (depicted on the mural above the sign) was a prominent member of the United Force ultras group and a figure linked to the Belgrade criminal underground. On May 9, 2022, at the age of 28, he was killed in a high-profile, professional assassination in Belgrade's Banjica neighborhood.