It's morbid... I'm scared.

Honestly, no. I think it is trying to sound profound but actually makes no sense to me at all on any level.

All those unknown to me are black, their minds stay in the darkness, haunting me, hurting me. i shall never be free from the dark, come into the light and let yourself be known to me. Mildly depressing mumblings from someone who (in the first three lines) appears to have a messiah complex and in the last three contradicts themself(intentionally?) by saying "I am the light, but always in the dark".(Imagine the Messiah being such an inneffective one that they're always in the dark.) All-in-all, quite cliché except for that little twist. Do I think it's good? Not my place to say, but I didn't particularly enjoy it.

It has potential. Tell your friend to keep writing, and reading.

In all honesty? It's truly dreadful. The only concrete image in it is the word "dark" and we aren't even told what the dark feels/ looks/ smells like, it doesn't tell me what it's about, it's purely abstract, doesn't have any discernable meaning (if they're unknown to you how do you know their minds are in darkness and why do you care? And how are they hurting you if they're in the darkness. Who are they anyway? And why should we care?) And what is it? Is it a poem? A random sentence? Why should I read it or care about its message (if it has one)? Good writing needs to give a reader something to latch onto, a reason to care. A satisfaction in the reading - this sounds like it might be the beginning of something, but what's the upshot? Put bluntly - what's the point? And all that blackness and darkness stuff has "teenage emo fan" written all over it. Generally any poem with the words "dark" or "heart" in is to be viewed with great suspicion. And what's with the re-ordrring of words? "come into the light and let yourself be known to me"? Who speaks like that? People generally only use those kinds of phrases when they're trying to be "poetic" Not that I didn't write equally bad stuff when I was younger.

Personally, I think it's better to be bold as to take some sort of lighting device with you and try to shed some light on those unknown subjects, so to speak.

It sounds to me like someone is trying to write a seemingly good poem that expresses deep feelings. It's like the writer was trying too hard. It doesn't make sense either. Why would someone unknown to you hurt you? I don't get it. Am I not supposed to get it?