The Observer is a member of the Collective who is currently following Noah Maxwell as part of his session. He previously followed Mary Asher and her son, Milo Asher, and has even claimed to have assisted Milo in committing suicide. He appears as a man with relatively long hair who wears glasses. Upon removing the glasses, his eyes have unusually small pupils, although at one point he was instead shown with one large eye in the center of his forehead.
The Observer was once known as "The Sentinel", but he was given the name "Observer" by Noah's followers. He has also described himself as "theeyes" and "asentinelbytradepasthisexpirationdate"; he has claimed to type in such a unique fashion because where he is, there is no space. He is seemingly using Noah's friend, Kevin as a vessel; Kevin, presumably his past self, has attempted to resist the Observer on numerous occasions, but has been largely unsuccessful.
He has the unique ability to see through a special symbol often referred to as the "Observer Symbol", which he has replaced the profile pictures on all of Noah's accounts with and is somehow preventing him from changing them back. As such, he has said that he is able to see anyone viewing one of Noah's accounts on their computer, but chooses not to, as most of them are insignificant. Creepy... He is also responsible for the distortion and hidden frames in many of Noah's videos, as well as uploading several full videos to his channel. The Observer is represented by the ♜ (black rook) chess piece.