Although it's not even a bl, it was my entrance into bl/yaoi, as well as manwha. It helped me realize my interest/obsession with the psychological genre, and led me to search for similar stories.The actual story was extremely interesting and made me cry.
This was the first manga to bring me psychological satisfaction since reading Killing Stalking. From here on, I also discovered my favorite mangaka: Harada.
This is representative of the series with this specific brother/couple.
This was titled "Drag-less Sex 2" on here when I read it. I prefer that name and it fits this spin-off series better.
This is representative of the whole series, although the last manga is still marked as ongoing on this site.
Killing Stalking