|“||I'm you, your rational mind. You're having a breakdown, a stress response. Your power is kicking in to save you. It created me. You did.||”|
|— David's rational mind conversing with David[src]|
After surrendering control of his body to Amahl Farouk, David Haller found himself trapped in a mental prison on the Astral Plane that took on the form of a pitch-black coffin. His rational mind manifested as a stress response to being imprisoned, and helped David come to the realization that the coffin was not real. David's rational mind then instructed him to imagine a classroom with a blackboard, with the intention of helping him piece together his history with Farouk. 
In the classroom, David's rational mind told him to forget all the memory manipulations and work off what they knew. Together, they were able to deduce that Farouk was a mutant who was psychically defeated by David's father. As revenge, the disembodied Farouk possessed David as an infant after he was adopted by the Hallers, feeding on David's own power to become strong enough so that he could exact revenge on his father. With this knowledge, David was able to break free of the mental coffin and free himself and his allies from the Astral Plane's version of Clockworks Psychiatric Hospital. 
- David Haller - creator
- Dan Stevens used his natural accent when portraying David's rational mind.