actually a spiritual being that helps you it will get dreams of random people to choose to help then he goes out to help them and through his visions and stuff he sort of warns the person like a guardian what to do and what to watch out
I'm not an expert but, you mentioned "banshee". and in Irish folklore, the female fairly (banshee) will appear as a foretelling of something bad happening to you. And your "guardian" or your spirit guide will try and help you choose the right path to take when in danger. I agree with PreacherCort, it sounds like actions of a spirit guide or totem.