The Infernal Trio is formed (at least in Khajidu's mind) by three Real-World Norwegian tall ships: Statsraad Lehmkuhl, Sorlandet, and Christian Radich. The term also designates the corresponding team of agents, respectively Whatever, South, and Krisprolls.
These agents are androids, with the personalities the Real-World ships would have if they had been sentient during their whole 'lives'. As there are striking resemblances between the three ships, Whatever was considered the father of the other two, and their personalities were built as such. The agents' android bodies age slower than human bodies, which makes them look roughly half their real age. In their point of view, they come from the Real World and were turned human for reasons still unknown to them, just before joining the PPC in 2009. However, their real-world, non-sentient, tall ship doppelgängers still exist.
The agents are located in RC #20736.