He uses his reach better than anyone in MMA history, by a wide margin. You can't get close to him, and if you do there is an elbow, knee, choke, or one of the best wrestling clinches in the game waiting for you.
He never has to take risks to win a fight. He just stays at range, picks his shots, and plays defense unless an easy opportunity presents itself. His fight IQ is outstanding and he rarely makes a mistake. He keeps it simple most of the time though and just always makes sure to be either in kicking range or clinched. There is no reason for him to hang out in boxing range to trade punches, box, shoot takedowns, etc - all things that would leave him open to counters or damage. He makes his opponents come to him and is content to coast to a decision if his opponent won't take the necessary risks.
Oh and a shitload of steroids.