Just by saying faber is evil doesn’t make him the ancient evil so far here are the points we have been givin:
-In the tenth terminal guilty spark says the ancient evil has risen again (Something a long the lines of this) there were no forerunners present on the ring only the flood and humans
-The primordial reffers to the precursors and the flood being the same
-The symbol at the end IS infact the didacts,frankie pretty much confirmed that
-Precursors are extremly deceptive and have the power to convince and control anything including AIs.
-Guilty spark says that if there are prometheans the didact would also have to be there and if the librarian isn’t there to temper his rage humans would preffer the flood
-There is speculation that the destruction of the ring and the ark could have awoken the didact
-Guilty spark/chakas says he knows where to find the librarian and takes over the Infinity,the infinity happens to land in requium.
-Cryptums are made for prometheans and what we saw in the trailer is confirmed to be a cryptum,the didact was a promethean.
-Faber was presumed dead on instalation 07
-The primordial says something a long the lines of you must kill me now so another can live possibly awakening another precursor
-All the precursors aren’t dead,they said they would return to test humans again with the flood in 100,000 years,which brings us to where we are now
-there are two factions of the promethean AIs on the planet one is orange and seems to be rampant the blue side seems to be normal
-All the forerunner technology we have seen so far has been blue unless rampant like guilty spark or cortana
-The didact isn’t evil nor does he have anything against humans.
-The didact was clearly active from when john entered or before john got there
-Mendicant bias says he was sending john to his creators to pay for his sins,the didact created him
None of that points to faber and those are all the hints we have been given so far.It all points to the didact being controlled by a precursor