Zack is a Giftia and a Marksman that is partnered with Michiru Kinushima, and works for the SAI Terminal Service Program. His personality is shown to be a quick-witted character, but also shows many degrees of compassion. Zack is also often portrayed playing quietly on his handheld video games, leading to his appearance of an antisocial character. He is also often portrayed teasing Michiru Kinushima's dialogues.