https://en.wikipedia.org/wiki/Antichrist

It's a later addition, does not refer to one individual only and is said to

... may have been generated by the frustration of Jews subject to often-capricious Seleucid or Roman rule, who found the nebulous Jewish idea of a Satan who is more of an opposing angel of God in the heavenly court insufficiently humanised and personalised to be a satisfactory incarnation of evil and threat same source.