Possible Clues:

• "Othello" role
• 'O, beware, my lord, of jealousy' speaker
• He helped get Cassio demoted
• Lodovico calls him a 'Spartan dog'
• Othello's Ancient
• Bad guy in 'Othello'
• Ensign positioned east of Santiago
• One gets a green light from such a playful villain
• "It is the green-eyed monster ... " speaker
• "So will I ... make the net / That shall enmesh them all" speaker