Janus

Janus is a mysterious individual who is clearly anti-Illuminati in his actions, evidenced from his involvement in Deus Ex: Icarus Effect, where he aids Ben Saxon and Anna Kelso in combating the Tyrants, a group of black ops mercenaries working for the Illumimati. He also makes an appearance in The Missing Link DLC, where he contacts Garvin Quinn in the ending cutscene, who speaks of recruiting Adam Jensen in their invisible war against the Illuminati.

Trivia

 * Janus dismisses Garvin Quinn's initial idea of recruiting Adam, stating that he is too obsessed with Megan Reed at that point in time. However, Janus also states "(Adam) will find the truth in due time" and that they would find Adam if Quinn followed Janus' instructions exactly.