incest is wincest (straight)

Not exactly dark, calming and somewhat serious, like reading in a dimly lit room on a rainy day.

Dark, fucked-up, rape, abuse, violence, everything fucked up. F.

fucked up, emotional incest? I'm not sure. Can skip this if you want.

This one was just painful. But realistic at the same time unrealistic.

I almost forgot about this one. Another shoujo classic and a classic incest too.

chapter 4. fucked up.

dark, calm, soothing in a weird way like reading in a dimly lit room on a thunderstorm day. Although, the 3rd manga where they're not blood related in this list, this is just too good to miss.

"What the fuck did I just read?" Yeah, exactly that. dark and will make you uncomfortable.

Fucked up max. dark, violence, coercion? but yeah, blood related, definitely.

Chapter 5. Blood-related. Calm and it took me hours to find it. Wish it was longer tho, or made into a series. The art is also subtly nice.