so Mephisto takes 3 sixes(I see what you did there), and some might call it Beyonder envy, but who cares. he teleports them in a hidden pocket dimention on 1 mile radious surphase with it's own atmosphere. he makes them start-off in furhtest points and informs them that there are 2 other teams, and that they can only return to earth with a great prize and chance to become his agents there, if the other 2 teams are completely dead(just play along). However he will not resurrect anyone.
No prep, because they are too busy looking for the other teams cause Mephisto gave them an unknown time limit(crafty bastard doesn't wanna miss cosmic's bingo night)
no knowledge of other teams.
the battle feild is empty ground
no BFR, by that I mean the ground littrly indestructible, and so is the atmosphere.
Which team would win? And how many/which members of that team would be still alive after the event ends?
Here are the teams: