Santiago Jilie Singh was a Laconian military officer with the rank of captain. Singh was married to Natalia, or "Nat", a nanotech scientist, and they had a daughter Elsa, roughly two years old, whom they call "monster".
He served as executive officer on the Cleo patrol ship.
Singh was appointed by Laconia's High Counsul and military dictator, Winston Duarte, to become captain of the Gathering Storm and governor of Medina Station following the colony's emergence from isolation about thirty years after Duarte arrived there.
Singh represented a generation of "greenblood" officers fully committed to Duarte's great man approach to imperial guidance, and viewed all humans as citizens of the new Laconian Empire.
Singh fully believed in the military structure, even reporting against his beloved commanding officer, Captain Iwasa, for dereliction of duty after Iwasa had refused to enforce the new Laconian naval code which would've subjected those under his command to death if they were found derelict for duty - punishment included being put in the "Pen", the site in which humans and animals were deliberately infected with Protomolecule for scientific research. Seemingly impressed by his commitment to the Laconian Empire, Winstone Duarte appointed Singh as acting Governor of the soon to be captured Medina station.
After Medina Station is captured by the Laconian Empire, Singh and his Crew of the Gathering Storm are assigned to garrison the station, ensure no traffic is allowed through the gate network so that Admiral Trejo's campaign to subdue the forces of Sol isn't interrupted and to also bring the colony worlds into the Laconian fold. During this time an assassination attempt is made against him by Medina's former security chief Onni Langstiver but Singh's assistant, Junior Lieutenant Kasik, was the only Laconian officer killed.
Shaken from the assassination attempt, Singh orders his head of security, Colonel Tanaka, curtail the freedom of Medina's population by implementing a curfew and roaming checkpoints. After Tanaka refuses to do so on the grounds that it will only fuel Medina's resistance, Singh relieves Tanaka of her post, despite the later's extensive experience in dealing with Belter's and the OPA. Tanaka's second in command, Major Overstreet, is then made Medina's security chief.
In an insurgent plot that included destruction of an auxiliary oxygen tank to cover up the theft of Laconian decryption codes, James Holden was captured and after Singh questioned Holden about the alien anomaly on Ilus that has now appeared on Admiral Trejo's ship, Singh put Holden on the Lightbreaker and sent him back to Laconia for further interrogation.
After the insurgents freed prisoners, disabled his marines' power armor, disabled sensors, took his ship and fled, he was humiliated and ordered Major Overstreet to put together a list of Laconian loyalists to cull all others, Overstreet revealed his standing orders to make an example of the governor if the situation presented itself then executed Singh.
- In Strange Dogs, Santiago is seven years old and the same age as Xan, a child born on Laconia to non-military settler that arrived before Duarte's men. This implies he had to have been born after Abaddon's Gate; however, in a conversation with Colonel Tanaka, he states he was a child during the Io Campaign. This makes his age inconsistent, he lied, or he has a younger brother/cousin with the same first name.
- Singh is the fourth antagonist to have viewpoint chapters in the book series, after Clarissa Mao, Filip and Marco Inaros.
- Captain Iwasa
- Admiral Goyer
- Admiral Trejo
- Colonel Tanaka
- Major Overstreet
- Commander Davenport
- Lieutenant Pilau
- Captain Fisher
- believed friend of Xan