The Halo 4 Crimson Map Pack, which is due out on December 10th has been outed - well, its various unlockables have, which is great news for PEOPLE WHO CANNOT BE PATIENT!
Sorry. Anyway, the pack of maps is the first of three multiplayer areas made available using the War Games Pass. More details? Sure...
According to Halo Waypoint, "it will cost $10.00 USD or 800 Microsoft Points and consist of three maps, a new Crimson DLC Matchmaking playlist, and eight achievements."
Those achievements are:
Now They Fly? - Get a kill while airborne in a Warthog. - 50 points
Size Is Everything - Kill 20 enemies with a detached Machine Gun Turret. - 20 points
ODST - Kill a player while you're airborne from using a Man Cannon. - 30 points
Bigfoot - Kill 20 enemies using the Mantis' stomp attack. - 20 points
David and Goliath - Board an enemy Mantis. - 20 points
Clay Pigeon - Shoot an enemy out of the air while they use the Man Cannon. - 40 points
Special Delivery - Kill an enemy with a melee attack when landing from a Man Cannon. - 30 points
Pump Yer Brakes - Score the killing blow on a Mantis. - 40 points
Source: Halo Waypoint