Who is Satan? Why is he allowed to exist? What do we know about him?

I was always taught that angels did not have a free will but then I heard that 1/3 of the angels rebelled with Satan. How can this be if they have no free will?

A Jehovah's Witness told a friend of mine that Jesus and Michael the Archangel are one and the same. Could you help us refute this?

Are the demons or devils fallen angels or did they come from a different place?

Paul begins his letter to the Romans with a declaration about the gospel. Then, after sending his greetings to the Romans, he tells them of his desire to visit them and be a blessing to them.

Zechariah speaks of the cleansing and service of Joshua, the high priest at the time of the return from Babylonian captivity. He also points to the coming of the BRANCH and the redemption of the land of Israel.