@Nermie01
From what I saw in the last couple chapters
They just keep their relationship as siblings. No kiss or anything like that.
The last 2 chapters are her birthday party and him trying to gift her a ring (I think it's an engagement ring?) but he fails to and says he will try again next year (he says as long as the possibility isn't zero, he will keep trying) . It ends with them meeting up on the street and her calling out Onii-chan.
She said in the last chapter "Present ira nai " don't want any presents this new year , but this clearly feels like the editor is forcing him to not cross the incest line ! So it isn't worth the read who has sister imouto , onechan fetish , clear warning
As an oniichan, I can understand how you attracted to your imouto because of her cuteness. But hell, sexually attracted to your imouto is just plainly sick. Such a degenerate manga. I love it.
The art is good, but fucking hell man. This is unironically a manga about incest, where one of the parties involved is even a minor, and the author decided that it was okay. Seriously, wtf?!?
Actually not too bad. If the author pulled the not blood-related card early and toned down the more explicit perversion, he might have escaped the "complete degenerate" tag, and the story might have worked yet.
But yh... Brother's a little too extreme in all the wrong ways for me to be comfortable with. Could have been funny.