Mark born before the Turbo Star accident involving Jim and Dread. Since Dread was always hostile and Dawn always busy, Mark didn't had a lot of interactions with his parents. He used to play with a girl named Laura Chen, who was his only friend.
While he was only a kid, Mark's parents supposedly died in a car accident. However, their bodies were never found. After these events, Mark's aunt and uncle, Roxanne Hunter and Charles Hunter, with much despise, took care of him. They constantly ignored him or were cold towards him, despite he still tried to impress them with good grades, a good behavior on school and others.
In the future, as a 17 years old teenager, Mark and his family moved to Copper Canyon. In the first day of school, Mark meets once again Laura and is eventually bonded with Psycho after he was chased by bullies. Initially though, like Max, Mark reacted negatively in being linked, but he eventually befriend X376 and both became good friends at the point of Mark stating that he was "the family that he never had".
Initially, they appear using the exact same Turbo Modes as Max Steel, as they were attempting to frame Max and Steel. Eventually though, after a tough battle, Max's T.U.R.B.O. Energy partially reboots X376, making their armor change and get the ability of generating their own Turbo Modes.
Mark possesses the same strength, speed and aglity as an average human. By generating negative feelings, Psycho can convert it into negative T.U.R.B.O. Energy, being purple instead of Max's blue energy. When linked with Psycho, Mark incorporates the Psycho Sycon persona, which is able to create Turbo Modes and many other abilities, similar to Max and Steel. If Max and Steel produce Turbo Modes, Psycho is able to copy them instantly and incorporate it to their arsenal.
Mark has red hair, blue eyes and tan skin. He has approximately the same stature as Maxwell. In his camouflage mode, he uses a grey t-shirt with the link port being in the right side of the chest where a white symbol is seen, similar to that of Steel's symbol, brown pants and black shoes.
- His name would originally be X376 Warrior, where X376 would completely take the control of the host and would use it as a puppet, and later Dark Steel.