A warm, impulsive biologist whose enthusiasm repeatedly brings him close to hazards Murderbot must pull him from.
Dr. Ratthi is a biology specialist of PreservationAux, best friends with Overse and Arada, and quietly attracted to Pin-Lee without acting on it. He favors inspecting the blank map region and joins the reconnaissance.
His map loses the hazard markers, so he and Arada unknowingly pass the safety perimeter. Later he walks into an acidic mud pit and Murderbot hauls him free, leaving them both coated to the waist. Ratthi is nevertheless selected for the DeltFall rescue as the group's biologist and boards the large hopper with Mensah, Pin-Lee, Overse, and Murderbot.
His physical features are not described. He wears survey gear and, after the reconnaissance, is memorably smeared with acidic mud to the waist.
Ratthi provides biological knowledge on the rescue mission, though his impulsive curiosity makes the team's security precautions necessary.