I've never read Bastard, and I don't know how dark is too dark for you, but I have a few comics.
The two comics by Sketchylinez:
Main Site: http://www.vermillionworks.com/daniel/
Tapas Mirror:
These comics are my favorites. I'm sure they're not all like the one you gave an example of, but they all have dark themes, some more than others. Hopefully at least one of them is to your interest.
I also have a darker psychological drama/character study revolving around themes of trauma, abuse, mental illness and sickness. All the characters kind of suck, you may feel bad for the MCs or you may not, it depends on your own perspective and experiences. If you're sensitive to any of the stuff mentioned or self-harm, blood, body horror, discussions of suicide, substance abuse, nudity and/or profanity this may not be for you. Read it at your own discretion. (Also it's drawn in color pencils, so if you don't like that aesthetic then you may want to skip it.)