Okay, so I read it and the first thing that stands out to me is the idea isn't bad, but its really hard for me to understand. I cant tell what tense it is in as it keeps flipping around. You also tend to use run on sentences and the spacing is confusing. And the misspellings of some words I can understand but there are others that look like complete gibberish.
In your description you write 'an' before a consonant but you only need to put that before a vowel, I.e.: "A successful" as opposed to "an successful". When you add the 'n' I think it's a typo for "an
unsuccessful" instead. Maybe it is, idk.
There is also the fact that you keep on bringing up information not explicitly stated or mentioned in the beginning of the chapter that is needed for flow. Like how he almost died, but somehow I didn't catch that part. And then they suddenly mention some "poor souls" that really seem to have no relevance to the plot so far.
Here's my suggestion: Start with the meeting and assert the "god" of darkness's evilness, (you can mention him eating souls here that way later on when he tries to bargain with the MC using them it doesn't come out of left field.) and then you can continue on with MC beating him down with the catchy song and tragic backstory. It's more cohesive this way.
As before suggested by
@tiaf Grammerly and Google Docs/Word can rlly help with grammar and punctuation, but for sentence structure and story flow I suggest you get an editor, as they can see it much better than any computer/editing software I've ever seen.
I think your story has a lot of potential, but it's like a diamond in the rough, you need to polish it. Good luck! ☆⌒(≧▽° )