Zack is a tall young man with blonde hair and blue eyes. He is almost always seen wearing the standard combat uniform and gear of the Red Constellation, consisting of black clothing covered with a series of red armour plates, various combat equipment and ammunition belts. Zack is most commonly seen wearing a full helmet which obscures his face, but he does remove it outside of combat situations. When acting as a bouncer for the club Neue Blanc, Zack wears a black suit. Zack seems to prefer using a huge blade in combat.
Zack is very respectful to his superiors in the red Constellation, obeying orders without question. Despite having left the corps, he extends this courtesy to Randy Orlando and shows his respect as the son of their former commander. Zack does acknowledge that the actions of the Red Constellation in Crossbell City may have caused some resentment towards the group when challenged by Randy a few years later. He does seem to enjoy life on the battlefield, noting that he envies the other members of the corps that get to fight in an 'amazing place'
Zack is amongst the forces of the Red Constellation that arrive in Crossbell City under the command of Sigmund Orlando and his daughter Shirley Orlando. They had been hired to provide extra security for Giliath Osborne, using their vast amounts of Mira to buy Revache's old headquarter and convert it into one of their clubs, Neue Blanc. When not in combat, Zack appears to act as a guard or bouncer for this institution, welcoming randy and his co-workers in on a couple of occasions, even when the boss wasn't there.
Zack is also present on the battlefield alongside the rest of the corps. He takes part in the slaughter of the Imperial Liberation Front at Orchis Tower and apologies to randy as the corps withdraws. He is also present in their various operations across the state, encountering and acknowledging Randy's strength, musing that they do not have particularly great anti-aircraft measures yet and holding back the Special Support Section whilst Sigmund and Shirley are busy elsewhere.
Zack returns as part of the forces hired by Dieter Crois to help retake the city from the Supreme Leader and the Black Guard. After this, he can be found discussing plans with Gareth in Neinvalli where randy confronts the pair about their actions when Crossbell was raised. At first stating that randy was quite rude, Zack does then acknowledge the feelings of resentment they might have caused.
Zack is presumably amongst the Red Constellation Forces that help assault Reverse Babel.