Scott Adkins breathed life into the Undisputed movies as Yuri Boyka. Beginning with the prison boxing movie Undisputed in 2002, the idea that there was even a follow-up in the works at all was rather unexpected, the film having largely evaporated from the public consciousness. However, when Undisputed 2: Last Man Standing came along, it took its namesake from a forgettable one-and-done to an engrossing and innovative MMA franchise.
Plenty of the credit for that deservedly goes to Michael Jai White and director Isaac Florentine. As the movie's lead character George "Iceman" Chambers, White was the rare protagonist that viewers couldn't wait to see get his butt kicked for his self-absorbed conduct, only for him to transform into a new man after realizing that his skills need refining. Florentine also fully brought the movie's Russian prison arena setting to life with his direction, and he has gone on to become one of the most respected filmmakers working in straight-to-video action movies. Still, Scott Adkins' performance as Yuri Boyka was the deciding factor in what made the Undisputed series into what it known as today.
From the moment viewers met him, Boyka was a unique character in every sense, an MMA fighter with the mindset that he's been tasked by God himself to become The Most Complete Fighter in the World. Though he began as a nominal villain in Undisputed 2, the movie was a classic case of the antagonist being the break-out character. Boyka fully took center stage in Undisputed 3: Redemption, continuing the series' tradition of making the villain of the previous installment into the hero of the next, but that trend was broken with the fourth chapter, Boyka: Undisputed, since it was obvious by then that Boyka was way too great of character to not be in the cockpit of the MMA-driven movie franchise.
Boyka evolves greatly over his three appearances. Though he consistently maintains his single-minded focus on being the world's greatest fighter, his loss in Undisputed 2 humbles him to overcome his bad knee and build himself back up in Undisputed 3. He also begins to genuinely repent for his misdeeds Undisputed 2, helping another prisoner to escape the rigged tournament at what he believes will be the cost of his own freedom in Undisputed 3, and later sacrificing everything he's achieved for himself to save the widow of a man he accidentally killed in the ring in Boyka: Undisputed. Throughout his story, Scott Adkins' portrayal of Boyka is the kind of performance where it's impossible to imagine anyone else in the role.
On top of that, when it comes to martial arts action, the Boyka-centric Undisputed movies deliver on their title and then some. Adkins is one of the most dynamic and versatile martial artists in modern action movies, and has long been at the frontline of the renaissance of straight-to-video movies regularly eclipsing theatrical action scenes. The fight scenes of the Undisputed films are as out-of-this-world as it gets, and Adkins has never been less than breathtaking in action in what has become his signature role.
It's a minor miracle that the Undisputed franchise is even a franchise at all with how minimal of a first impression it made in 2002. Three sequels later (along with a proposed TV series continuation), the series is more beloved than could ever have been expected. With how its story has played out, it's safe to say that the Undisputed franchise would never have reached the heights that it has without Scott Adkins as Boyka.