Iron is a Halo 3 Campaign Achievement. It is earned when the player finds the Iron Skull. This Achievement gives 10 Gamerpoints to the player.
It is represented by a blue circle with a skull in the middle. The skull has a hammer on its forehead.
The Iron skull can be found on "Sierra 117" on Normal, Heroic, or Legenadary difficulty. To get it, at the end of the level at the dam, you must jump onto the pipe walkway and go to the farthest corner.
Effect: When either player dies in Co-Op on any difficulty all players will restart at last checkpoint. When a player dies in single player on any difficulty, the entire level will restart.
Related Links