Simultaneously killed two Wardens in The Breaking on Heroic difficulty.
Completed Swords of Sanghelios co-op with both Mantises on Heroic difficulty.
Destroyed the Phantom at the Covenant camp in Reunion on Heroic difficulty.
Simultaneously destroyed 2 cores in Guardians on Heroic difficulty.
Teamed up in a vehicle to kill 30 enemies in Unconfirmed co-op.
Worms Don't Surf
Knocked two Hunters into the ocean during the Battle of Sunaion.
Completed The Breaking on Legendary difficulty without the entire fireteam dying.
On My Mark
Simultaneously assassinated two Elites in Blue Team co-op.
Enemy of my Enemy
Helped the Elite General charge the hill in Osiris on Heroic difficulty.
Operated four different vehicles at once in Mission 13 on Heroic difficulty.
Death from Above
Killed a Grunt and smashed a grate with a Ground Pound in Battle of Sunaion.
Kept 6 miners alive at the elevator in Evacuation on Heroic difficulty.