
Incest based on bloodline, it because you share same DNA with your bloodline family that's why it forbidden. Because combinating same DNA make teribble result. In case Haru and Ren, it isnt incest at all. They just adopted family, their relation is just on paperwork made by society, not bloodline.

People will come up with the same excuse "bloodline", just to avoid reality, cause apparently their moral views wont accept this manga as "Incest". But ether way it's incest, their brothers. Also, their is no definition that states incest is between bloodlines, the original definition which you seam to have skipped over says incest is sexual relation with family members with the same bloodline and those related by marriage, adoptions, step-relatives, ETC. You get the point already.
Those who defend this manga with bare teeth, and swear that this isn't incest. I wonder would you guys fuck your adopted brother/sister because it's just a "paper" made by society. Would you really be willing to face the criticism, and disgust, you'll receive for your actions. I honesty doubt it. Since your actions, your thoughts, your behavior are all controlled by the society you live in, you'll soon jump on board and follow the norm.

You do know this is a fictional story, right?

mmm but they're not brothers at all, i mean ... they don't see each other as brothers ,not in the start and now even less ( at least i didn't feel like they were brothers) , well just my opinion(〜 ̄△ ̄)〜sorry for my english

You do know i am replying to the comment above, or did you just forget. My opinion is related to his comment. I wont hold back my thought just because this is a fictional story...

well okay, but that doesn't mean you have to be so mad about it. ╮( ̄▽ ̄)╭

Dude, it's not excuse at all. Based on thesaurus dictionary, incest is (i'm copy and paste this) sexual intercourse between two persons commonly regarded as too closely related to marry it can be they shared same bloodline or by marriage. No, dude. Step-relative isnt. (And fyi, in japanese gay marriage forbidden either, so many of them will adopt their partner as brother and sister to register in family. Do you think it kind of incest too?) Besides. If you read the manga carefully, you will know either of Haru and Ren dont think they are brother. They care each other but isnt as brother, the other people outside of family who think that why because Ren registered as Kaidou Ren. That's the issue.
And you exaggerating here, talk about disgust, face the critism bla bla bla like, people talk that way about gay marriage in 1950 you know. besides, we all know this is manga. Why you pointing to people and think they will fuck their step family just because they like this kind of manga. Are you think people here cant diferentiate manga and real life or what? Last, do you ever think that paper by society can be changed but bloodline not? Do you ever think why society potrait it wrong? The reason? Because the reason is like i said before, combinating same DNA make terrible result. That's why.

The seme egocentric and douche, but he get my hat when he nearly raped the uke and when look at the uke face in edge of crying he stop it. after that he trying to avoided the uke because realise more than the chikan and prevert around the uke, he's more dangerous but he cant stop worrying. It's kinda cute. I'm glad he confess properly tho.
Gotta go lesbian for his mom lol