Yuri Boyka (portrayed by Scott Adkins) is the champion of the maximum security prison Chornya Cholmi who initially appeared as the antagonist of the film Undisputed II and the protagonist of Undisputed III and IV. Boyka became known as "The Most Complete Fighter in the World" after dozens of consecutive victories, which earned him the reputation of Undisputed until he faced American boxer George "Iceman" Chambers which led to his first known defeat in his long career. Boyka has a total of 47 matches (including the rematch with Chambers) throughout the franchise. He was introduced having 34 fights plus the remaining 13 matches from the 2nd film all the way to the fourth film in the franchise. Boyka has a record of 46 wins and 1 loss. Boyka accidentally killed fighter Viktor Gregov in their fight and this would be a remarkable event in his life that would turn him to a better man. He promises to help Viktor's wife with the money he would win from the fourth tournament. After winning it and beating Koshmar along with his whole entourage including Zourab Boyka asks his wife forgiveness in her husband's death which she doesn't respond. Boyka was arrested shortly before being sent to his former prison in Russia. 6 months after the incident Boyka was visited by her informing him that she had finally forgiven him. Feeling relieved, Boyka get back his old ways as the king of prison fighters still aiming for the title of the most complete fighter in the world.