Marcus Armstrong is a playable character in Emma storyline with specialization of melee attacking wanzer.
He is originally a commander of USN marine squad in a Taipei mission. During the siege of Taipei, his squad is eliminated by Changli Army and he's the only one that still alive. He went to USN ambassador in Taipei to investigate the possibility of his betrayal that causes the partial failure of the mission.
During the battle in USN ambassador, he used artillery tank and fight along side the Kazuki's team. After the battle, he joins the team.
In Alisa storyline, Marcus is an enemy that fights them in Futai Tunnel.
His starting wanzer is Grapple M1A that will show its full potential with dual, same melee weapon.
In outside of battle field, he is a father of twin girls and an alcoholic. In photo of his daughters wearing ninja suit sent by email, when it is processed by Kaleidoscope tool, it shows an UFO. It is not quiet sure what it means.