Doctor Ira Graves is the main antagonist of the Star Trek: The Next Generation episode "The Schizoid Man".
He was portrayed by the late W. Morgan Sheppard, and also by Brent Spiner while possessing Data.
Ira Graves was one of the foremost scientists in the Federation, doing advanced work on molecular cybernetics. He was also egotistical and chauvinistic. He claimed to have taught Noonien Soong everything he knew. He lived in seclusion on a planet he named Gravesworld, the only other inhabitant being his young assistant Kareen Brianon. Without his knowledge or approval, Kareen sent for help when she realised Graves was ill.
The Enterprise needed to answer another distress call so dropped Data, Worf, Troi and Doctor Selar off on the planet. Selar quickly determined he was in the end stage of the incurable Darnay's Disease. Graves took a keen interest in Data, telling him to refer to him as his grandfather. He revealed that he had developed a process to transfer his mind to a computer, cheating death to an extent. However, with Data on the planet, he now had an alternative: He instead transferred his mind to Data's body after deactivating him, then let his body die.
Graves' personality soon became dominant in Data's body, delivering an egotistical eulogy for himself and demonstrating deep resentment and jealousy towards Picard. He approached Kareen and told her who he was, indicating they could finally be together. However, Kareen was unnerved by his behaviour and, failing to understand the strength of his new body, Graves crushed her hand.
Graves then headed for Engineering where he injured two of the staff in a rage. He insisted the injuries he'd caused were accidents and argued that he had more right to live than Data. Picard tried to insist he abandon the body and Graves struck him in a rage, accidentally knocking him unconscious. Realising the danger he had become, Graves transferred the contents of his mind from Data's body into the ship's computer. His consciousness failed to survive the transfer, leaving him effectively dead.