Dude, you are really hard on yourself about this. Even Shakespeare drew from the works of people before him. You don't have to re-invent the wheel. Even if you're using well-established plot devices, the important thing is to own them, make them your own, and give them your own voice. That's all that matters.
This.
My story starts off as an incredibly cliche tale of the hero who sets out with his
romance options bestest friends ever - the mysterious older mentor and the kid mage - and goes to go save the world from the revival of the evil god that's supposed to take place every ten years.
That's deliberately cliche, because it's what happens afterwards - when he finds out that literally everything he thought he knew about the situation and the people around him is an elaborate lie - that it becomes original. I'd try to summarize the plot with a reference but honestly I can't think of anything that turns things upside down the same way I intend to.
Also, if it's any consolation: Chances are your work is nothing like Disgaea. Stuff focused on demons isn't entirely uncommon, but there's a hell of a lot of room for originality in it. And if it
is accidentally like Disgaea, well that's fine too because A) you didn't realise it beforehand, and B) Disgaea is -awesome- and if you ended up creating something like it by accident you should feel awesome?
