In the Greek tongue the word
"antichrist" means "instead of Christ".
Lucifer will pretend to be Christ, claiming to be Christ... William won't claim to be Christ or pretend to be Christ.

Lucifer is The Son Of Perdition. The son of perdition is to stand where he ought not in Jerusalem on The Temple Mount...That would be supernatural Lucifer.
William is not supernatural...William
is a human, natural flesh human.