This is the antagonist in a Brothers Grimm-esque story idea I am developing involving two children, Peter and Glenda Friedman, getting lost Hansel and Gretel style off in the woods one day while going to visit their uncle.
This third child, identifying himself as Hans Düssel, appears and seems to be friendly and give them help, but is in reality misdirecting them, because he is actually an evil, soul-devouring abomination in the guise of a friendly child (and may or may not be possessing the body of a previous victim), who schemes to kill and eat our heroes and take their souls.
He appears as a normal human boy except for his eyes, which are light green with dark green irises. As to why this doesn't tip Peter and Glenda off that there's something wrong with him? Fairy tale logic. Here in this pic he is sitting on a tree branch playing his enchanted flute (he has a Pied Piper-esque vibe to him) looking deceptively sweet and innocent.