The first point is I want to clarify the addition of "[OC?]" into the title. This is because although the protagonist really is the soul of Madara, he suffers from amnesia which he must recover from for a large part of the novel. In addition to having his own unique backstory, the experiences he has in Douluo Dalu make it so that his personality grows a certain way outside of these memories.
In essence, he is an original character(OC) in the sense that he is his own being who has access to Madara's memories and powers to help him.
Next, the story is currently no harem. Personally, I often mind them meaningless to include, especially considering I am not doing R-18. The story will continue to be no-harem unless I see an overwhelming(I mean OVERWHELMING) vote for such as I will keep 'doors' open in that sense.
Third, protagonists develops his own powers. He is not going to be a Madara clone by having every ability Madara is known for having. He has Sharingan and more, but understand if the powers are not exactly identical to those seen in Naruto.
That is all I can think of at this point. I will return to make additions to this if I see the need. For future chapters, you will be able to know by reading the author's thought section where I will mention it.
No upload schedule at the moment