Master Sergeant Marcus P. Stacker is a veteran Allied Marine Shock Trooper who fought during the First war. He was assigned to the 7th Battalion of the 105th Shock Division and is currently stationed on UNSC Infinity. Marcus P. Stacker is a tough and energetic marine. Although he can be quite reckless in certain situations, he is a very competent leader who has seen his fair share of war. Having survived many battles including all discovered Halo Installations, Stacker has fought alongside BJ Blazkowicz on many occasions, often providing assistance in vital situations.