There is a lot of ruckus over this, everyone seems to have a different answer. I think shadow people are just left over energy of what used to be there. But be wary of what lurks in the dark. But...
You have to get soul drops to make your people strong but you can only use it once. You can get other soul ORBS to level them up on any one. The Max level is 10. The best one i would recomend you use...
Because he absorbs or reflects light like any other solid object. Yes that and the fact that everyone and everything will have and always has had a shadow.