Rick is from season 3, pre Lori's death. Joel from the Last of us, and Robert Neville, from the 2007 film I am Legend, Merle has both hands.
Round 1: All have a Machete, a rifle with 4 rounds, a shotgun - 6 rounds and a Colt Python, 6 shells.
Start in Piccadilly Circus London, London, Midinight. The Rageinfected from 28 days later are scattered throughout the area, but there are not many. They start 300 yards from one another in stealth. Win by death morals on and bloodlusted. They have been immunised from the rage virus.
Round 2: Same scenario all armed with only a knife.
Round 3: All unarmed in a bar fight. Win by ko or death. Bloodlusted
Round 4: Merle and Daryl vs Rick and Shane vs Joel and Tess. Standard gear. Morals on. Bloodlusted. Fight takes place in New York City at midnight with some walkers in the area. Win by death, incap or KO.