No no not a spirit at all, it's a creature/being in its own. Spirits are past away people like we all know and hate, ghosts basically. But shadow lurkers are just that, they're a being on its own that are formed from shadows, im not sure really how they form but they're always around and they always observe. They're just....there. I guess. If you sit in total silence and you hear that sort of screeching noise from it being too quiet, if you listen past that you'll hear them whispering. And then they know that you know about them, they can be harmful only if you provoke them and aren't friendly. Other than that they're harmless and quite nice to be around.