So they are not really brother related by blood but more like a cousin since both masumi and yuki mother are twins and their mother run away together when they give birth to masumi and yukio.
It starts off really bad, but what do you know??? it just kept getting worse!! like it can still get worse than that??? oh yeah it did. last chapters are - I just can't.. like seriously, WHAT THE ACTUAL FUCK.
This is so messed up... why does the smut have to be so hot and yet so fucked up?! Why do authors even write shit like this and then have the audacity to make the smut so good