Marcus Reid
From Tardis Wiki, the free Doctor Who reference
Marcus Reid was the trooper assigned to guard Krisztina and knew of her in his youth. He liked to skip-stones, and the Sixth Doctor called him a geologist's nightmare. He loved Krisztina. He disappeared 5 years ago. He was the son of the palace gardener. He was killed in the Killoran attack. (AUDIO: Arrangements for War)