Sakai is an OPA employee on Tycho Station.

He took over as chief engineer on Tycho Station after the death of Samara Rosenberg in the Slow Zone Incident. Sakai oversaw a major retrofit of the Rocinante after its return from the human colony on Ilus. He was responsible for sabotaging the fusion reactor containment software with a subroutine that would collapse the magnetic bottle, destroying the ship and anything nearby.