Through life people see things they can not understand or told that they do not exist, such as ghosts and UFOs. One example is encounters with angels. The definition of an angel is an agent or servant of divine power, a spritual being who travels between different realms and can perform miraculous acts.
They are known in all religions, but can be tempted and corrupted, so then becoming servants of the darkside(or lucifer). The true angels represent purity and kindness. An example is during world war one when allied armies in belgium found themselves close to defeat, then suddenly the german cavalry stopped and retreated. Eye witness accounts from both sides describe the sudden appearance of groups of angels hovering in the sky. So through many experiences angels may exist, religious or not, its a comforting thought.