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The Expanse Wiki

The Human-Protomolecule Hybrid was part of the secret Project Caliban program to use the Protomolecule to develop super-soldiers.


To create the Hybrids, children were kidnapped and taken to Prospero Station on Io, an officially shut down station. When it was time to test a Hybrid in combat, one was secretly unleashed on Ganymede to attack UN Marines who drew the Hybrid towards Martian Marine Corps forces nearby. Signals to the surface were jammed and United Nations Navy and Martian Congressional Republic Navy naval forces, believing each side had attacked the other on the surface, engaged in orbit. The Hybrid successfully killed all but one Marine Bobbie Draper before a bomb detonated in its body destroying it.

A second Hybrid was later unintentionally released due to a grenade tossed by Amos Burton that damaged its containment system. The Hybrid proceeded to quickly kill the researchers and guards assigned to it before breaking through an airlock and escaping into the Ganymede landscape. The crew of the Rocinante proceeded to give chase, but elected not to kill it after an intensive debate. However, while the crew was distracted, the Hybrid was able to enter the Rocinante cargo-bay, where it was then successfully destroyed by luring it out into space using the core of a nuclear warhead and destroying it with the ship's Epstein drive.

On the surface of Io, a Hybrid (formerly Katoa Merton) was unleashed by the Protogen staff and was engaged by Bobbie Draper, who successfully defeated and killed it.

Numerous Hybrids were placed into stealth pods and fired from Prospero Station against Mars. These pods were all destroyed by ships in the A.O. and Long-range nuclear missiles operated by Tycho Station OPA.


  • Hybrid was stated to be 9 1/2 (nine and a half feet) tall standing up straight, what is 289 cm (289.56)