There are four Ghosts directly under the ramp to the left as you exit the control room. They will not show up if the level is started from Rally Point Alpha or if played on a Solo Campaign. The only way to get Ghosts in the mission is to play on Legendary Co-op from Mission Start until the end.Make sure that everyone doing the achievement is sure that they won't log out of the game midway because there's nothing more annoying than having to restart the level after someone's connection disconnected when you were almost at the end.On the circular corner platforms, take the time to knit your group and perform a head count, as well as inspecting your Ghosts and thinking of good routes.All players should have their headsets on for better communication.If the players reach a replacement vehicle during the ending run, they may use it only if his/her Ghost is destroyed. This does not mean the other three aren't required to ride Ghosts. Even though all players must ride a Ghost, only one of the players is required to reach the end on a Ghost for all four players to receive the achievement.

Halo 3 odst legendary ending