From Shoryuken Wiki, Marvel vs. Capcom 3 Strategy and More!
Originally created in ASG Lab 7, a mechanical body now supports Brain Drain's empowered mind. Now that everyone has conveniently forgotten what happened to Lab 7 and the rest of Brain Drain, he's become "psychic director" of the highly secretive ASG Lab 0. Peacock, Leduc, Ileum, Big Band, Hive, and the other creations of ASG Lab 8 appear to have free will and stay on friendly terms with Dr. Avian. Brain Drain controls Painwheel against her will, suggesting a more villainous set of ethics. Valentine hates Brain Drain and may have been forced to work on the kidnapped Carol though mental dominance.
If made a playable DLC character, Brain Drain would attack his opponents with advanced technology paired with his overpowering psychic abilities. His body language most closely resembles Magneto, his cocky attitude resembles Slayer, and the general chip on his metallic shoulder invokes a bit of Dr. Doom. Fighting with an array of bizarre drugs, mind control, lasers, robotic minions, and hallucinations is enough to make players completely lose control of their characters or make the enemy team fight itself. Depending on the implementation, Brain Drain could easily be overpowered to the point where he only makes sense as a boss character.