What's this anti cheat thing? I ask out of curiosity, but i only play single player. is it "always online only play" kind of deal?
It was a Denuvo Anti-cheat update (added after the game's release) which used some kind of kernel-mode driver which had very high-level access to your system.
It was for multiplayer but I believe it was installed regardless of what mode you played.
It's been removed but, as they added it without warning after release, who's to say they won't try to sneak it back in again?