Stage One Subjugation: Subjugation By Proxy
When the Outsiders first detect or encounter a new alien species, they attempt to find a fringe group, collection of outcasts or other form of rebel element to use in order to sieze control of the species. In humanity's case this was the unreg faction that called themselves the Renegades, though the majority of the unregs in the faction were unaware of this. The fringe group is aided by the Outsiders with technology, supplies and construction abilities in order to give them the ability to stage a coup on the rest of the species, as the Renegades attempted with the Second Unreg War. It is known that this was also attempted with the Children of the Sun, but the Tongue of the space station "Into The Darkness" (Feathers on the crest of the distant flock) refused to betray its species and the station was destroyed by the Outsiders.
If successful, the target species as a whole may never become aware of the fact that they are under the control of the Outsiders, aside from its specific leaders. However, out of the three species that have had dealings with the Outsiders and information is known about (humanity itself, the Jinu and the Children of the Sun) none of them successfully entered Stage One Subjugation, although in the case of the Jinu, their alliance with humanity may have been responsible for the skipping of Stage One.
It is assumed that Stage One is fairly rare due to this.