Cero

Cero is a young Zero who wanders the Veit due to a deal made with the Ayatana. He has total control over which possible outcome an event had or will have, but uses this power sparingly.

Early Life
Cero was found on the front steps of an orphanage and lived there until he was found to be strongly resilient to facsimile presentation at the age of ten during a visit by a state examiner. This was when people resilient were just being identified and it was highly vilified. He was sent to a regional experimental prison for observation, during which time he was incarcerated in the same cell as a disguised Payton, who over the course of the following seven years became increasingly obsessed with Cero.

At the age of 13, a guard beat Cero to the point of death. A makeshift blood transfusion with some of Payton's blood both allowed him to survive and activated his ability to see facsimiles.

Eventually, Payton helped Cero stage an ambitious escape attempt, telling him to head to the Academy.

The Academy
Cero attended the Academy, the most advanced observation center for resilient individuals in the region, for around a year, during which time he learned the basics of facsimile presentation and understood the power he had by being able to determine reality. Upon learning the reality of the situation of resilient individuals (called zeroes at the time) from a professor there at the time, Cero was convinced to leave the Academy with his ethics professor, Virgil.

Ayatana
After nearly dying at the hands of Buchanan and requiring more of Payton's blood to survive, Cero was perfectly suited to house Ayatana despite his terminal illness. She offered a deal: his body for her to roam the earth in for a century, in return for his body healing. He would spend that interim time as the sole inhabitant of the Veit, except for the strays, with full control over the reality of the past and future, able to change almost anything he wanted, including bringing Virgil back to life. He accepted her deal and entered the Veit, a half-land of almost-realized realities that exists on top of our own, like a ghost landscape of missed lifetimes. He removed the cube containing virgil's death and put it in a different, missed timeline- essentially bringing Virgil back to life in our own.

At the time of The Strays, Cero has been an inhabitant of the Veit for ten years. Ayatana roams the planet with his body.