Zack Meverford was a character in Space Siblings. He stood with Dylan. He takes in everything very negatively - if there is laughter, he believes it's because others are making fun of him. If something goes wrong, he is certain that someone is trying to sabotage him. He feels that no one gave him a fair chance in life and is angry at the world - looking for opportunities to lash back.
Zack was always a thug as a child. He would push kids without provocation and take their lunch money. Naturally, he was destined to join Dylan in his quest. Though Zack has some hidden soft spots, the overwhelming evil in his constitution always overtakes and engulfs any faint glimmerings of potential good.