1 John 2:18 Little children, it is the last time: and as you have heard that antichrist will come, even now are there many antichrists; thereby we know that it is the last time.
The Anti-Messiah is coming refers to a proper name and a particular leader. It also mentions many individuals. So both are true. There are many that deny Yeshua is the Son of G-d and have the spirit of the Anti-Messiah. Today this is definitely the case and tells us it is the end of the age.
How can we tell that they are anti (against) Messiah?
1 John 2:19 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.
The fact that they left us reveals they were never genuine believers to begin with.
1 John 2:20 But you have an anointing from the Holy One, and you know all things.
1 John 2:21 I have not written to you because you know not the truth, but because you know it, and that no lie is of the truth.
Ruach HaKodesh imparts spiritual truth to us.
1 John 2:22 Who is a liar but he that denies that Yeshua is the Anointed? He is antichrist, that denies the Father and the Son.
1 John 2:23 Whosoever denies the Son, the same has not the Father: (but) he that acknowledges the Son has the Father also.
1 John 2:24 Let that therefore abide in you, which you have heard from the beginning. If that which you have heard from the beginning shall remain in you, you also will continue in the Son, and in the Father.
1 John 2:25 And this is the promise that He has promised us, even eternal life.
1 John 2:26 These things have I written to you concerning them that seduce you.
1 John 2:27 But the anointing which you have received of Him abides in you, and you need not that any man teach you: but as the same anointing teaches you of all things, and is truth, and is no lie, and even as it has taught you, you will abide in Him.
This verse is not saying we should not have leaders or teachers. We do not have to depend on them to know the truth. We can read it for ourselves. Ruach Hakodesh will also reveal the truth to us.
1 John 2:28 And now, little children, ABIDE in HIM; that, when He shall appear, we may have confidence, and not be ashamed before Him at His coming.
A genuine trust and love for the coming of Yeshua will produce in us a willingness to be morally pure when He returns.
1 John 2:29 If you know that He is righteous, you know that every one that does righteousness is born of Him.
We should follow His example. Abiding in Him is also Abiding in the Father. A person should see the love of Yeshua in me.