I know what you mean by having a person unexpectedly ‘show up’.
Through my adult life there seems to be an elderly looking man with a funny beaked hat who seemed to make the scene when I was in a potentially dangerous situation. I believe he’s an angel.
My sister was a dorm director in a college while she taught at another college. It turned out she was the only person left in the dorm when school let out. She could hear the elevator going up and down. (Scary) The LORD allowed her to see past the walls into the hallway where there were two giant angels posted at her door. One was sitting on a table and was talking to the other one who was sitting on the floor. I remember she said they had yellow hair, big wings, white robes, and golden belts and sandals.
Angels are all around us, but can only be activated through God’s Commands.