Both teams get 1 week prep.
Ultron and Thanos have to beat Batman, Superman, MM, WW, GL and Flash in a battle. (All current versions)
Darkseid and Brainiac have to beat Black Panther, Thor, Charles Xavier, Iron Man, Silver Surfer and Capt America in a battle.(current versions)
Villains have no artifacts(gems, cubes and the like). Spaceships and minions allowed. 1 month prep for villains. At least 80% of earth has to survive the battle. Villains win by killing all heroes. Who will kill faster?
Heroes will fight to the death (obv) and are bloodlusted.
All villains at peak (but no artifacts).