Who is Antichrist?

The word, antichrist, is only used in the Bible in the epistles of John. John uses the word five times in four verses (1 John 2:18Little children, it is the last time: and as ye have heard that antichrist shall come, even now are there many antichrists; whereby we know that it is the last time.
See All..., 1 John 2:22Who is a liar but he that denieth that Jesus is the Christ? He is antichrist, that denieth the Father and the Son.
See All...; 1 John 4:3And every spirit that confesseth not that Jesus Christ is come in the flesh is not of God: and this is that spirit of antichrist, whereof ye have heard that it should come; and even now already is it in the world.
See All...; 2 John 1:7For many deceivers are entered into the world, who confess not that Jesus Christ is come in the flesh. This is a deceiver and an antichrist.
See All...). These verses show that there is one who is the Antichrist (1 John 2:18Little children, it is the last time: and as ye have heard that antichrist shall come, even now are there many antichrists; whereby we know that it is the last time.
See All...), that there is a "spirit of antichrist" (1 John 4:3And every spirit that confesseth not that Jesus Christ is come in the flesh is not of God: and this is that spirit of antichrist, whereof ye have heard that it should come; and even now already is it in the world.
See All...), and that there are numerous antichrists (1 John 2:18Little children, it is the last time: and as ye have heard that antichrist shall come, even now are there many antichrists; whereby we know that it is the last time.
See All...; 2 John 1:7For many deceivers are entered into the world, who confess not that Jesus Christ is come in the flesh. This is a deceiver and an antichrist.
See All...). The word, antichrist, means "against Christ." However, the word is also used of one who is a false Christ. The three uses mentioned above need to be defined:

Antichrist. This use of the word refers to that particular one who will come during the time of tribulation, not only to oppose the true Christ, but to declare himself to be the Christ. In Daniel 9:26And after threescore and two weeks shall Messiah be cut off, but not for himself: and the people of the prince that shall come shall destroy the city and the sanctuary; and the end thereof shall be with a flood, and unto the end of the war desolations are determined.
See All..., he is "the prince that shall come shall destroy the city and the sanctuary." In 2 Thessalonians, he is "that man of sin" and "the son of perdition" (2 Thessalonians 2:3Let no man deceive you by any means: for that day shall not come, except there come a falling away first, and that man of sin be revealed, the son of perdition;
See All...), "the mystery of iniquity" (2 Thessalonians 2:7Shall they not rise up suddenly that shall bite thee, and awake that shall vex thee, and thou shalt be for booties unto them?
See All...), and "that Wicked" (2 Thessalonians 2:8And then shall that Wicked be revealed, whom the Lord shall consume with the spirit of his mouth, and shall destroy with the brightness of his coming:
See All...). In Revelation, he is the first beast (Revelation 13:1-8 [1] And I stood upon the sand of the sea, and saw a beast rise up out of the sea, having seven heads and ten horns, and upon his horns ten crowns, and upon his heads the name of blasphemy. [2] And the beast which I saw was like unto a leopard, and his feet were as the feet of a bear, and his mouth as the mouth of a lion: and the dragon gave him his power, and his seat, and great authority. [3] And I saw one of his heads as it were wounded to death; and his deadly wound was healed: and all the world wondered after the beast. [4] And they worshipped the dragon which gave power unto the beast: and they worshipped the beast, saying, Who is like unto the beast? who is able to make war with him? [5] 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. [6] And he opened his mouth in blasphemy against God, to blaspheme his name, and his tabernacle, and them that dwell in heaven. [7] And it was given unto him to make war with the saints, and to overcome them: and power was given him over all kindreds, and tongues, and nations. [8] And all that dwell upon the earth shall worship him, whose names are not written in the book of life of the Lamb slain from the foundation of the world.
See All...). The epistles of John do not in any way deny the  coming of the one final Antichrist, but only looks to another application of the term.

Spirit of antichrist. 1 John 4:3And every spirit that confesseth not that Jesus Christ is come in the flesh is not of God: and this is that spirit of antichrist, whereof ye have heard that it should come; and even now already is it in the world.
See All... tells us that the false doctrine that Jesus Christ did not come in the flesh is of the "spirit of antichrist." From this, we can conclude that any doctrine that denies that Jesus is fully God and fully man subtracts from who He is and is therefore against Christ. It is the spirit of antichrist.

Antichrists. 1 John 2:18Little children, it is the last time: and as ye have heard that antichrist shall come, even now are there many antichrists; whereby we know that it is the last time.
See All... warns us that "even now are there many antichrists; whereby we know that it is the last time." From these scriptures, we can see two kinds of people who are antichrists. First, there are those who deny the fullness of Christ either in His humanity or in His deity. They are antichrists because they spread teaching that is against Christ. Second, there are those who falsely claim to be Christ.  Jesus warned, "For many shall come in my name, saying, I am Christ; and shall deceive many" (Matthew 24:5For many shall come in my name, saying, I am Christ; and shall deceive many.
See All...). He also prophesied,"For there shall  arise false Christs, and false prophets, and shall shew great signs and wonders; insomuch that, if it were possible, they shall deceive the very elect" (Matthew 24:24For there shall arise false Christs, and false prophets, and shall shew great signs and wonders; insomuch that, if it were possible, they shall deceive the very elect.
See All...). As the day of the coming of the true Christ draws nigh, there will be more and more deceivers who either deny that Christ was all the Bible says He is or who will claim to be Christ themselves. These deceivers must be opposed.