The new maps are called Daybreak, Outcast, and Perdition. The maps tend to focus on objective game types that offer vehicle use, which should make those happy that like this sort of setup.
Halo 4 fans will be able to purchase the Castle Map Pack starting on April 8th for 800 Microsoft Points or about $10 for those scoring at home. For those on the Halo 4 Season Pass, The Castle Map Pack is the third and last map pack that was included in the Halo 4 War Games Season Pass. It is unknown at this time if this will be the last release of DLC for Halo 4 or not. No one is talking about that, but we doubt it at this point.