2 Thessalonians 2:3-4- Let no man deceive you by any means: for that day shall not came, except there come a falling away first, and that man of sin be revealed, the son of perdition(the loss of the soul); Who opposeth and exalteth himself above all that is called God, or that is worshipped; so that he as God sitteth in the temple of God, showing himself that he is God.
Our bodies are the temple of God:- 1 Corinthians 3:16- Know ye not that ye are the temple of God, and that the Spirit of God dwelleth in you.
1 Corinthians 6:19-20- What? know ye not that ye are the temple of the Holy Ghost which is in you, which ye have of God, and ye are not your own? For ye are bought with a price: therefore glorify God in your body, and in your spirit, which are God's.
So "the" antichrist will sit in his own body showing himself that he himself created everything of meaning in the world- because he doesn't believe that there is a true God who created all things and holds all things together. This man will deny that Jesus is of any significance- and will explain away anything that points to a creator as evolution and anything that points to a savior of the soul that allows a relationship with the creator as a fairytale.
It never actually calls this man "the" antichrist- actually there are many anti-christs.
I John 2:18- 25- Little 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. They went out from us, but they were not of us; for if they had been of us, they would no doubt have continued with us: but they went out, that they might be made manifest that they were not all of us. But ye have an unction from the Holy One, and ye know all things. I have not written unto you because ye know not the truth, but because ye know it, and that no lie is of the truth. Who is a liar but he that denieth Jesus is the Christ? He is antichrist, that denieth the Father and the Son. Whosoever denieth the Son, the same hath not the Father: [but] he that acknowledgeth the Son hath the Father also. Let that abide in you, which ye have heard from the beginning. If that which ye have heard from the beginning shall remain in you, ye also shall continue in the Son, and in the Father. And this is the promise that he hath promised us, even eternal life.
So an antichrist is someone who denies that Jesus is God. Everyone knows of Jesus:
Romans:18-20- For the wrath of God is revealed from heaven against all ungodliness and unrighteousness of men, who hold the truth in unrighteousness; Because that WHICH MAY BE KNOWN of God is manifest in them; for God hath showed it unto them. For the invisible things of him from the creation of the world are clearly seen, being understood by the things that are made, even his eternal power and Godhead; so that they are without excuse.
Even if people have never heard of the man Jesus Christ they know of his spirit through the spiritual world.
If someone is spiritually denying Jesus (which everyone has done at some time) it is an easy condition to fix- Romans 10:13- For WHOSOEVER SHALL CALL UPON THE NAME OF THE LORD SHALL BE SAVED.
What is hard is describing to an unsaved person what Jesus is because they do not see Jesus as a person. They see Jesus as something separate from the person of Jesus Christ in the Bible. They do not know that what they see spiritually is Jesus because they see Jesus in other people and think that that is the people when actually it is Jesus.
The only way to help a person see who Jesus is to talk about him and write things about him and that will help a person see that Jesus Christ is in fact what they like about people in this world and what they are attracted to spiritually.
The true spirit of antichrist is when a person has their own agenda and they have no room for the spirit of Christ in their life and they harden their heart against him because they see him as a threat to their wants and desires- Of couse if a person hardens their heart against the spiritual aspects of Christ they can learn who Christ is through the Bible and other people and be saved by calling upon Jesus/ God just as a person who has never hardened his/ her heart against Christ can- but when this happens the salvation is different because the person starts to experience conviction from the holy ghost about how they live and the consequence will be that they start to change themselves and what they do.
When a person is saved they will start to enjoy communicating with others about Jesus and God and how good the Lord is, which they didn't do before
because before they were in the dark about what Christianity was about.