#1 Daniel Cormier

This one is a no-brainer, actually. Daniel Cormier is one of the greatest Mixed Martial Arts of all time. He has achieved all there is to achieve in the sports by becoming only the second fighter to hold two Championships simultaneously. The current UFC Light Heavyweight and Heavyweight Champion, Cormier has openly stated that he has only a few fights left and hopes to bid adieu to the sport when turns 40 on next year's March.
He is scheduled to defend his Light Heavyweight Championship later this year and is penciled for a fight against Brock Lesnar, where he will be putting his newly won Heavyweight Championship on the line. This fight will most likely be taking place early next year as Lesnar still has a few months left on his USADA suspension. Cormier will most likely announce his retirement after the Lesnar fight.
Cormier is the biggest Pro Wrestling fan in the UFC and has attended many major WWE events. He was in attendance when Seth Rollins cashed-in his MITB Contract to become the WWE World Heavyweight Championship at WrestleMania 31 in San Jose. The video of DC celebrating his friend Rollins win went viral on social media. DC will be the biggest catch for the WWE considering the kind of legacy he has left on the octagon.