You could've had a good dunno, neightbors/childhood friends or whatever, but no, had to waste the good art on siblings...
Edit: LOL Didn't read the incest tag, this one is on me.
this is an amazing series. everything is perfect, it has exactly everything i was looking for... a high quality real sibling incest romance without stupid love triangles, really great dialogue and amazing art... the only thing i can say is chef’s kiss