Stem, like other AIs, is cold and direct but also polite. He possesses vast knowledge and the ability to work with computer data and programs. He quickly masters the function of the human body, allowing him to do things beyond average. However, he has a dark side - he wants to become human and is willing to do whatever it takes to achieve this goal. He is manipulative and convinces Grey to take revenge on his enemies. His ability to organize all of this shows that he is scheming.