I just finished reading two stories from a series of dark fantasy short fiction, called Into Shadow.
As advertised, these stories were dark and even violent, but not gratuiously so. They were also very well-written. Though each be read in an hour or two, I found them both to be powerful, though in different ways.
"The Six Deaths of the Saint," by Alix E. Harrow
This one was my favorite—though easily the darkest. It deals with a seemingly endless cycle of war and violence. The heroine of the story is a young girl, "rescued" from poverty by an ambitious prince, and trained to use her practically super-human skills as a fighter to be his saint (or devil) and fight in his cause. Yet no victory satisfies him, no advancement in power is enough. He always wants more. It explores the question of how far someone might go, how far they might be complicit even when they begin to realize the truth, in order to win the love and approval of someone who pretends to care for them, but really only finds them useful.
"What the Dead Know," by Nghi Vo
This one was more chilling, because the setting was closer to our own world, and because apart from the supernatural element the terrors the story unfolds were all-too-realistic: prejudice against women, prejudice against foreigners, a woman's death at the hands of her violent lover. The heroine here is a fake medium of Vietnamese descent. Along with her love and partner, Maryse travels a setting similar to the 19th century American Midwest pretending to communicate with the dead, although in truth she has no such power and doesn't believe that such things are possible. Then one day in a small isolated town, a missing woman decides to use Maryse to reveal her tragic fate.