Daniel 10: 10-21 gives us a glimpse into the events that are occurring all around us as a part of the angelic conflict, but are invisible to our eyes. These are things that would remain unknown to us but for divine revelation. I am providing a link that gives a short commentary on Daniel 10, regarding the prince of Persia, who is a fallen angel. He is hindering a messenger angel from coming to Daniel in answer to Daniel's prayer.
Prince of Persia | Learn The Bible