Chapter 13 continues with the conflict that will take place between the dragon and the church of God. But in chapter 13, he changes the symbolism from dragon to beast. In chapter 12 it was a pagan institution that fought against God’s church, as represented by the devil. In chapter 13 the devil disguises himself in the form of a "Christian" institution to persecute the church of God. He is good at disguises.
The beast comes out of the sea. Again, the sea represents peoples and nations. As in Daniel, chapter seven, the little horn came up among the nations, so the beast, the same entity as the little horn, comes up among the nations. It "resembled a Leopard, but had feet like those of a bear and a mouth like that of a lion." If you noticed, these symbols are in exact reverse order of Daniel 7:4-6. That is because Daniel is looking forward, and John is looking backwards at this point.