Nathaniel Garro was a captain of the Death Guard Legion who refused to turn traitor when Horus rebelled. He stole the frigate Eisenstein, carried word of the betrayal to Terra, and died fighting his own primarch during the Siege of Terra.
Who was Nathaniel Garro?
Garro was Captain of the 7th Great Company of the Death Guard, a Space Marine Legion that would later fall to Chaos. Born on Terra in the region called Albia, he joined the Legion when it was still the Dusk Raiders, before Mortarion was found.
He earned the honorific Battle-Captain and was one of the few Terran-born Marines still serving by the time of the Horus Heresy. His stubborn loyalty to the Emperor and old Legion traditions made him an outsider among his brothers, who mocked him as Straight-Arrow Garro.
The flight of the Eisenstein
When Horus turned against the Emperor at Isstvan III, Garro and his loyalists seized the frigate Eisenstein and ran. They fought through the Isstvan system, carrying news of the betrayal to Terra.
That warning gave the Imperium its first real chance to prepare for the civil war. Garro’s escape turned him into a symbol of defiance, and later the Church of the God-Emperor named him its first true martyr.
Agentia Primus of the Knights-Errant
After reaching Terra, Garro didn’t retire. Malcador the Sigillite recruited him as Agentia Primus of the Knights-Errant, a secret order of agents who worked outside the Legions.
In that role he hunted down threats to the Imperium, searched for a living saint, and operated in the grey space between loyalist and traitor. He remained a ghost, as Malcador put it, serving a cause that few would ever know about.
Death and legacy
Garro died in 014.M31 during the Siege of Terra, killed by his own gene-father Mortarion. He fell defending the Imperial Palace, ending his life as he’d lived it: loyal to the Emperor.
His story is told in James Swallow’s Garro audio dramas and the collected anthology. He’s remembered as the first martyr of the Imperial Creed and a rare example of a Space Marine who chose conscience over Legion.
Key facts
- Captain of the Death Guard’s 7th Great Company
- Born on Terra, in the region of Albia
- Escaped Isstvan III aboard the frigate Eisenstein
- Became Agentia Primus of the Knights-Errant under Malcador
- Killed by Mortarion during the Siege of Terra, 014.M31
- Called the first martyr of the Imperial Creed
FAQ
Was Nathaniel Garro a loyalist?
Yes. He stayed loyal to the Emperor when the Death Guard turned traitor under Mortarion. He fled Isstvan III and warned Terra of the Horus Heresy.
How did Nathaniel Garro die?
He was killed by Mortarion during the Siege of Terra in 014.M31.
What is the Eisenstein?
It’s the frigate Garro and his loyalists stole to escape the Isstvan system and bring word of Horus’s betrayal to Terra.