Possible Clues:

• Regularly save genial criminal influencer
• Bad musician sang -- vile wobbling
• Leaving work after starting something for sinister controller
• A compelling figure in orchestration, Gil Evans
• Controlling sinister character in George du Maurier’s Trilby
• Sinister influence of seconds, see, on English boxer
• Charmer leaving snakes under schoolboy's cap
• One who seduces and exploits young women — eg anvils (anag)
• Controlling type
• Evil hypnotist’s son leaving to reform