shadow beings: evil or no

I have seen these beings on numerous occasions. They appear bald with no definite gender and sometimes have white almost glowing eyes. They stand in the corner of my eye and wait, watching. If I notice them and turn to look, the disappear behind the wall they were behind or they will fade or run away while fading. Once or twice I have seen them in pairs. I think they mean no harm, but are neutral or are here to protect me but no one can truly know.