This is too similar to Jagaaaan, which has the same author as this manga. This annoying prick babbling about being the best etc is practically the same thing as the police officer in Jagaaan that ate graphite sticks all the time.
The endgame is to tell a forbidden love kind of story. Didn't you notice that in all these 54+ chapters? I don't see anything about the author's true colors being shown just now, everything was obvious from the get go. If you're still here despite all that, I don't know what to tell you.
Damn, I just want to see them happy together, having lots of babies and making never ending lovey dovey sex. I hope she comes back to Yoshida after she's 18 and they manage to be lovers.
So this uncle is the one who'll make her do pornographic material? Notice how she's hesitant to say she trusts or likes him. When Tomoka-chan asks if Nagi gets on well with him, she replies she went to her grandma's house to play before. And when Tomoka says "good thing he came then", Nagi...