Crimson

Crimson may refer to the following:
 * CRIMSON, a codeword classification protocol used by the UNSC.
 * Fireteam Crimson, a SPARTAN-IV fireteam serving aboard the UNSC Infinity.
 * Crimson Map Pack, a map pack for Halo 4.
 * Dedicated to Crimson, an achievement for Halo 4.