The Grand Marshall was the leader of the Ice Warriors.
- You may be looking for another Grand Marshall.
He was similar in appearance to Ice Lord Slaar, although he wore a more ornate helmet. He spoke normally (rather than the hoarse, loud whispers used by some Ice Warriors), as he was in 'his own atmosphere'.
He was killed, along with the rest of the Ice Warrior fleet, when Slaar's homing beacon was hijacked by the Second Doctor, sending them crashing into the Sun. (TV: The Seeds of Death)