Halo 5: Guardians

Prison Break

Simultaneously killed two Wardens in The Breaking on Heroic difficulty.

Worms Don't Surf

Knocked two Hunters into the ocean during the Battle of Sunaion.

Harbinger

Completed The Breaking on Legendary difficulty without the entire fireteam dying.

Double Stuff

Simultaneously destroyed 2 cores in Guardians on Heroic difficulty.

Preying Mantis

Completed Swords of Sanghelios co-op with both Mantises on Heroic difficulty.

No Witnesses

Destroyed the Phantom at the Covenant camp in Reunion on Heroic difficulty.

Maverick

Teamed up in a vehicle to kill 30 enemies in Unconfirmed co-op.

Enemy of my Enemy

Helped the Elite General charge the hill in Osiris on Heroic difficulty.

On My Mark

Simultaneously assassinated two Elites in Blue Team co-op.

Savior

Kept 6 miners alive at the elevator in Evacuation on Heroic difficulty.