The Dorian 3 Incident was an obscure Necromorph outbreak happened in 2250. The Incident takes 258 years before the First Aegis VII incident.
A year prior to the incident a Marker was discovered on a small backwater planet called Dorian 3. The planet was mostly populated by colonists who had been terraforming the planet. The marker was discovered by a construction team. They have contacted EarthGov and two days later they sent a research team. The marker had been placed into a research lab on the planet, but the workers who found the marker started to experience insomnia and uneasiness. Days later multiple homicides and suicides happened amongst the colonists. A week later all contact has been cut from the planet.
Before losing all contact one of the research team member was able to send out an encrypted SOS message to EarthGov.
Three days later EarthGov decided to send in a special forces unit to re-establish contact with the planet. Among the crew was a covert EarthGov agent with a special mission.