Big spoilers here but if you are reading this I assume you have played already?
Does/did Corvus exist in the real events of the game? As far as I know, Taylor was wounded on the Lotus Tower fighting Stone. For some reason he undertakes the DNI surgery (I don't if it was voluntary or he was just hurt bad and had it done to him so he would survive much like the Player), and this is when Kane leaves him (her appearing after surgery plus that cutscene make more sense now). He heads to the Coalescence building, confronts Kreuger about The Black Project (maybe not that exactly, I haven't read the mission intro scripts in a while) and keeps hush about it. Which is why I believe he is a higher rank than Hendricks on the first mission.
But I don't know if Corvus existed or not, and if it did, what happened to it?