The word "antichrist" not only means "against", but also "in place of".
The antichrist will not only be against Christ but will want to be worshipped in place of God and Christ!
Notice the following...
Matthew 18:19-"Again I say unto you, That if two of you shall agree on earth as touching any thing that they shall ask, it shall be done for them of my Father which is in heaven. 20 For where two or three are gathered together in my name, there am I in the midst of them".
In the midst of (or among) what/whom?
His believers/His followers/His body/HIS TEMPLE!
Don't you think that the antichrist (in wanting to be worshipped "as God" and in place of the true God and His Christ) will not claim this for himself?
In Matthew's account, this is one of the passages in which Jesus is asserting His Deity. Because only God by His Spirit can be "in the midst" of any group of His followers of 2 or more at all times.