Frax is to Ransik what Circuit is to the Rangers. He creates weapons and devices for the team, and even built the machine which took them back in time. On the surface, Frax seems to be a loyal robot who exists only to serve Ransik. What they don't realize is that Frax has his own agenda, and constantly devises his own schemes behind Ransik's back. He has his own private army of mutants, thanks to his discovery of the infamous X-Vault - prison to the most vile criminals. He despises both humans and mutants, and plans on one day having robots rule the world.
Frax was not always a robot though. He was once an upstanding human know as Dr. Fericks. He showed an ailing Ransik kindness, only to be betrayed. Ransik burned down his lab, and left him for dead, but Fericks survived, and transformed his body into a robotic one, becoming Frax. The once kind doctor now only knew how to hate. He joined Ransik's forces, plotting to take him down one day like he did to him. Ransik eventually discovered who Frax was, and had him hunted down and turned into arobot, which piloted Doomtron to its own destruction.