The Cobra character who is a master of disguise and leader of the Dreadnoks is Zartan.
Zartan is one of Cobra’s most distinctive operatives in the G.I. Joe: A Real American Hero universe. His specialty is infiltration: he uses masks, makeup, vocal imitation and, in some versions, advanced holographic technology to impersonate other people. He is also known for changing his skin color to blend into his surroundings, although that ability varies by continuity.
Zartan first appeared in the Marvel comic series in 1984 and became a major villain in the 1985 Sunbow animated series. He commands the Dreadnoks, a biker gang that works as Cobra’s mercenary shock force. His younger siblings, Zarana and Zandar, later joined the gang and expanded the family connection.
A common mix-up is confusing Zartan with the Baroness, Destro or Dr. Mindbender, who are also senior Cobra figures but have different specialties. Zartan’s defining combination is disguise, espionage and Dreadnok leadership.