Todays episode is a long time coming. Know your enemy is reference to the devil, the shatan, Iblis.
Before we get started let's make a reference an earlier show the shatan is not an angel he is a jinn.
The shatan is mentioned over 77 times. One of the first time he is mentioned is the story of our Father Adam (AS). He is said to be a jinn among the angels. He was expelled from Paradise due to his arrogance by not prostrating to Adam.
"What prevented thee from prostrating when I commanded thee?" He said: "I am better than he: Thou didst create me from fire, and him from clay."