It calls him The Beast and the Man of Perdition (he may be called the later elsewhere). You’re right that it is a spirit of antichrist, but there is a person who will rise (or may be here already) who John the Apostle called The Beast.
The Beast -— early Christians regarded as Roman Empire and Nero. If you read anything at all about Nero, you can understand why he could be called the Beast. He was a venomous predator snake in a human body.