Um right not reading that its not my trigger
Not to be mean though
Anyways, what you could do is just trigger triggers when the trigger is triggered to trigger triggers that make them fight.
For example:
Triggering Trigger - fires every X seconds that revives every hero in a variable storing every hero, checks if they are currently playing etc. Then moves them along the walls of the arena (or whatever your gonna do). Then pause them all
Triggered Trigger from the Triggering Trigger - Once the triggering trigger is triggered this picks 2 random heros from the unit-group, moves them to opposite sides of the arena, then unpauses them to fight and says FIGHT and they fight cuz ur supposed to fight after you fight untill ur all dead! MUAHAH
Triggering trigger after the triggered trigger is triggered: After one of the units die, remove them from the group and revive them in the losers pen (LOL) Then put the winner back on the wall. Now add him to a different unit group and remove from the current one. Now pick 2 from the first one and do it again untill theres nobody left in the normal unit group.
Trigger that is triggered from the last triggering trigger after the triggered trigger is triggered: After all the units are dead do basically the same thing over, and over and over untill theres only 1 man left. Then hes the winner. Remember to heal thier mana and health, and gold to winners.
Finishing trigger triggered when the trigger that is triggered from the last triggering trigger after the triggered trigger is triggered: When theres 1 man left move all the peoples back into the game, maybe you could store thier locations in a point array. Now you can unpause them all etc...