- "This isn't the first time one of you Bulldogs has come in here, looking to 'cause trouble."
- —Mustang to Archie[src]
Mustang is a member of the Southside Serpents.
Very little is known of Mustang's life. He currently resides on the southside of town, and some time prior to the start of the series he joined the Southside Serpents, a dangerous biker gang of criminals and thugs.
As he minded his business at the Whyte Wyrm, Mustang was approached by Archie Andrews, who asked if he liked beating up on kids. Mustang had been mistaken for another individual they were looking for, but he had no problem with granting Archie's death wish. He recalled the last time a Bulldog came into the bar looking for trouble, which presumably was a reference to Jason Blossom, so he pushed Archie, but then Archie pushed back. Unfortunately for the teen, he was out muscled and thrown on to the pool table, but FP Jones, the leader of the Southside Serpents, broke up the fight before matters got any worse. 
Mustang is a middle age man of medium height with pale skin, blonde hair, and bright blue eyes. He's only had one on-screen appearance, meaning knowledge on his wardrobe is limited, but what is known is that he dresses like the typical Southside Serpents, ragged clothing accompanied by a standard Serpent leather jacket. At first glance, he comes off as a dangerous dangerous, which is precisely what he is.
Due to having such a small role, there is not much known of Mustang's personality, but from what was seen, he's a ruthless thug, who is quickly angered. Mustang did not hesitate in his attack of Archie Andrews, suggesting that he has no problem with beating up kids. However, this should not come as much of a surprise because he's a Southside Serpents.