Ok. Pretend a firefight type mode where it's you and your "team" vs every damn creature in the game. Yeah sounds bland, right? Well.. Picture this. You're in the last city, and hobo goblins are sniping your 12 teammates from building tops. Devil Walkers are roaming the streets. Thrall are rampaging against you. Colossus Cabal are laying down the heavies. Vandals on Pikes driving around. A FireTeam of 3 leaves. Now you're down to 9. You start loosing ground. Since you only have a limited amount of lives, they force your team back. Then Vex teleport around your team. Trapping you. Suddenly, a new FireTeam of 3 appears. You're team is at 12 now, and you start treading through the enemies. Wizards flying around, poisoning your team, and an ogre appears. About 45 minutes goes by, and your team is finishing off the last walker. Time for rewards. Legendary engrams. No blues, greens, whites, or yellows. Just 2 legendary engrams. So you'll always get a good reward and if you do about 5 of these wars a day, you'll have a good chance at an exotic.