Ringmaster

Ringmaster is the leader of the Circus of Crime.

Biography
At some unknown point, Ringmaster created the Circus of Crime.

Ringmaster intended to steal a virus named Mythrax to sell it. At this point, Swordsman took his old student Clint Barton to Ringmaster, to be accepted into the circus as an archer.

The Circus of Crime faced the Avengers, and Ringmaster used his illusions to escape them, but they reached him. As a last resort, Ringmaster treathened the Avengers with a vial of Mythrax if they didn't let him go, but Redwing made him drop it and he found out that the vial was empty, as it turned out that Swordsman secretly worked for Zodiac and had taken the Mythrax. Ringmaster was subsequently arrested.

In the Comics
His power is hypnosis rather than the illusions seen in the TV series