Stage Four Subjugation: Subjugation By Extinction
If a species continues to attempt to rebel during Stage Three Subjugation and actively resists the Outsiders, there will come a point where the Outsiders consider the cost of controlling the species to outweigh the use of it.
At this point the species enters Stage Four Subjugation and as the name implies, the Outsiders attempt to exterminate the entire species and wipe it from the universe.
Humanity has learned from the Children of the Sun that this is relatively rare but does occur, and that the Children of the Sun themselves have aided the Outsiders in performing Stage Four on more than one species in their time as Battle Thralls.
Humanity entered Stage Four Subjugation in February 2309, but due to the reappearance of an augmented Percival Lowell was able to hold off Outsider forces until humanity could capture the regional mothership assigned to humanity and intern the Outsider overlord Zmnyaz.
This appears to have put the Outsiders in disarray, and has given humanity some time to prepare for their slow but inevitable response.
