The antichrist is the satan himself that appears in the form of the god of the unrighteous religions, while the antichrists are the unrighteous clerics/clergymen/believers of the same religions. They are proud and think that they may be Gods/Fathers/Lords/Christs/Firstbegotten/Masters, thinking/heaving themselves for wiser than the true Lord God, and believe in other gods and christs.
1 John 2:18-23 "Little children, it is the last time: and as ye have heard that antichrist shall come(ie that satan recruits/raise powers), even now are there many antichrists(ie unrighteous clerics/clergymen/believers); whereby we know that it is the last time. They went out from us(ie from the holy scriptures/traditions/word/preach), 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 that Jesus is the Christ(ie who denieth that Jesus is the one and only Christ)? He is antichrist, that denieth the Father and the Son. Whosoever denieth the Son, the same hath not the Father: he that acknowledgeth the Son hath the Father also.",
John 10:7-9 "Then said Jesus unto them again, Verily, verily, I say unto you, I am the door of the sheep. All(ie all christs/lords/messiahs/firstbegotten) that ever came before me(ie that in general came/exist/comes except Me) are thieves and robbers: but the sheep did not hear them. I am the door: by me if any man enter in, he shall be saved, and shall go in and out, and find pasture.",
John 14:6-7 "Jesus saith unto him, I am the way, the truth, and the life: no man cometh unto the Father, but by me. If ye had known me, ye should have known my Father also: and from henceforth ye know him, and have seen him.",
Matthew 24:4-5 "And Jesus answered and said unto them, Take heed that no man deceive you. For many shall come in my name, saying, I am Christ; and shall deceive many.",
Matthew 24:11-12 "And many false prophets shall rise, and shall deceive many. And because iniquity(ie the religious/spiritual unrighteousness) shall abound, the love of many shall wax cold.",
Matthew 24:23-26 "Then if any man shall say unto you, Lo, here is Christ, or there; believe it not. 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. Behold, I have told you before. Wherefore if they shall say unto you, Behold, he is in the desert; go not forth: behold, he is in the secret chambers; believe it not."
This physical world also is Kingdom of Jesus Christ: 1 Corinthians 10:26 "the earth is the Lord's, and the fulness thereof.", Hebrews 1:10 "And, Thou, Lord, in the beginning hast laid the foundation of the earth; and the heavens are the works of thine hands:".