Since Nephi had seen a prophetic vision of the complete disintegration of civilization among the children of Lehi from 400 A.D. to 1400 A.D., the Lord then wanted Nephi to see how Satan would spread darkness over all of the earth. Nevertheless God would gradually open America to the Gentiles of Europe and change everything. First, Nephi sees the work of Satan's great and abominable church trying to get control over all the Gentiles.
It is interesting that Satan's church is not a particular denomination. It is described as all those who fight against the Lord's work among the children of men. This is the way described it in 1 Nephi 22:14. When the gospel was restored the Lord said: "Speak against no church, save it be the church of the devil."1 This means to fight evil emanating from Satan and his angels, but not attack any particular denomination.