James Cutter

Cutter is a UNSC Naval ship commander. He plays a prominent part in the upcoming Ensemble Studios game Halo Wars to an unknown degree.

Battle of Harvest
Cutter was the commanding officer on the  during the ships first battles against the Covenant at the Battle of Harvest from 2525-2531.

However, "Captain" is a generic term for the commanding officer of a ship, Cutter may be almost any rank, ranging from Commander to Admiral. It is likely, though, that he is either a Commander, or Captain(the actual Naval rank).