Use the Advanced Solo rules from Dark City:
Advanced Solo Mode
Stryfe and Mr. Sinister rely on their Master Strikes to reach their full power. To include the full number of Master Strikes, you can use Advanced Solo Mode for any Mastermind and Scheme. It is the same as the Original Solo Mode from the Legendary™ rulebook, with these adjustments:
• During setup, include all 5 Master Strikes.
• Whenever you complete a Master Strike, play another card from the Villain Deck.
• When a Villain or Mastermind Tactic tells “each other player” to do something, do it yourself.
• Whenever you complete a Scheme Twist, instead of KO’ing a Hero from the HQ of cost 6 or less, put that Hero on the bottom of the Hero Deck.
That final point is key for playing some Dark City Schemes solo, so that they don’t end too quickly.