They've been seen in the ring as some of the world's meanest fight champions, but not many know who they are in real life.
After meeting the champions and seeing what drives them to glory, they go head-to-head and expose what they really think of each other behind the scenes.
Darko Stosic is Serbia's best current MMA champ; following his injury recovery; seeing his humble beginnings; meeting his family and reviewing his heavyweight title win and defense.