Actually, by strict definition "Anti-Christ" would be anyone opposed to Christ. "Right" and "Morally Correct" are not the same thing. Right, wrong and moral correctness are colored by observation and personal viewpoint. An Anti-Christ character would have to be right or correct quite often. If they were a complete nitwit or buffoon then they would never be able to gain or keep any type of political or military power. You would also have to have people that honestly felt or believed this guy was right, correct and worth following. People from all walks of life from the common man up to rich, powerful and intelligent individuals. Has he always been an Anti-Christ type of personality or was this something that grew over time?
For about the first three books. The further they got along, the more cartoony he got. Further, the people around him were often portrayed as complete buffoons. And "biblical' is subject to interpretation. If it weren't, there wouldn't be a google-plex of denominations out there who think they all have the "real" truth. But yes, I would call him "anti-Christ". Because that's what he's intended to be. And I would write him with layers, nuance and humanity. Else he would not be interesting at all. I wouldn't watch, that's for sure.