Revelation calls the Antichrist "the Beast". Paul calls him "the Man of Sin, the Son of Perdition". Daniel has many names for him including "the Little Horn", "the prince that shall come", "the king of fierce countenance", etc. It does not matter since this man not only stands in opposition to Christ, but claims to be Christ and God. Hence antichristos (in place of, as well as in opposition to).
But carefully note what John said, and he himself indicated that "the Antichrist" would come (as opposed to the many antichrists throughout history).
Little children, it is the last time: and as ye have heard that [the] Antichrist* shall come, even now are there many antichrists; whereby we know that it is the last time. (1 John 2:18)
I have place [the] in brackets before "antichrist" and also capitalized that word, since for the majority of evangelical Christians (and even unbelievers) there will be such a person.
Strong's Concordance
*antichristos: antichrist, (one who opposes Christ)
Original Word: ἀντίχριστος, ου, ὁ
Part of Speech: Noun, Masculine
Transliteration: antichristos
Phonetic Spelling: (an-tee'-khris-tos)
Definition: antichrist, (one who opposes Christ)
Usage: antichrist, either one who puts himself in the place of, or the enemy (opponent) of the Messiah.
Thayer's Greek Lexicon
STRONGS NT 500: ἀντίχριστος
ἀντίχριστος, ἀντιχρίστου, ὁ (ἀντί against and Χριστός, like ἀντίθεος opposing God, in Philo de somn. l. ii. § 27, etc., Justin, quaest. et resp., p. 463 c. and other Fathers; (seeSophocles Lexicon, under the word, cf. Trench, § xxx.)), the adversary of the Messiah, a most pestilent being, to appear just before the Messiah's advent, concerning whom the Jews had conceived diverse opinions, derived partly from Daniel 11:36ff; , partly from Ezekiel 38; Ezekiel 39.
So you are clearly mistaken in thinking that there will be no such person. Indeed God will give him and Satan 3 1/2 years (42 months or 1260 days, or time (1 yr) + times (2 years) + half a time (six months) to take TOTAL CONTROL of the inhabitants of the world. This will be the first half of Daniel's 70th week of years (7 years).
And they worshipped the Dragon [Satan] which gave power unto the Beast [the Antichrist]: and they worshipped the Beast, saying, Who is like unto the Beast? who is able to make war with him? And there was given unto him a mouth speaking great things and blasphemies; and power was given unto him to continue forty and two months.