Devil Queen Lilith, bastard daughter of the fallen demon lord (unknown even to her father). Unexpected inheritor of his dark magical gifts and the remnants of his army of darkness.
Demons, dragons, monsters, greenskins, beasts, undead, witches, bugs, automatons.
Pretty much anything you can associate with a dark lord, the apocalypse, or evil creatures, her father had it serving him, and now that he and his princes are dead, it is hers to command.
Her mother died giving birth to her and she was raised in a convent as an orphan, her life track was planning to be a nun for the god of light, father to all.
Her evil began to show when all of a sudden hr powers began to show, at first it was her getting severely ill from eating the garlic in what used to be her favorite dish, but started seeing the girls and women around her as mighty tasty, especially those souls within them, positively bursting with life energy.
Then it was that everything from silver to sunlight to holy water was burning her painfully.
Next she was summoning hellfire by accident and she unintentionally set everything around herself aflame before running away, scared of whatever was happening to her, she used to be totally incapable of using any sort of magic, now she had too much power and no training on how to wield it.
Finally the light of the full moon hit and she transformed into a devil, her skin turned red, her eyes turned yellow and slitted, her her hair turned white, her teeth grew sharp, her finger hooked, and she grew her horns, wings, hooves, and a tail, her heritage as the devils daughter was finally revealed.
The whispers of the abyss echoed out from the shadows, singing her a happy 13th birthday, and calling her the "lucky girl", telling her of her true inheritance as the new lady of evil, wishing her luck in avenging her father and brothers by killing the hero, and completing the destiny of the devil by conquering the world.
Unexpectedly, she had no interest in being evil, but she was smart and immediately tricked the shadows into teacher her how to empty the water of the nearby lake, using hr magic she transported the water back to the orphanage and put out the flames, she then improvised a healing spell to save as many of her sisters and mothers as she could, finally she raised the ones who had died and refused to enslave them as servant zombies, but rather kept them as free-willed intelligent zombies, the only issues she had was that she could no longer set foot (hoof) on holy ground without burning (from light/holy damage, not fire).
Meanwhile, the forces of heaven were also busy, they interrupted the hero at his dinner with his family to tell him of the final hidden inheritor of the dark one's bloodline, that he must go to her and slay her to prevent her from ascending once again. She's already burned down an orphanage and is raising the dead as the first of her army.
His daughter overhears the conversation and recognizes the name: Lily, her best friend, sister even, from back in town. Her father did not know much of his daughter of her life since he spent so long out fighting evil, but she managed to assure him that her bestie was the best and would never harm anyone. There had to be a misunderstanding. As the daddy's girl of the chosen one, and due to him wanting desperately to reconnect with his kids, he was willing to hear her out.
Later on, the lady Lilith was reshaping herself back into her mortal form, the shadows are uncertain as to whether she wants to play along or not, does she actually want to conquer the world, or is she just bluffing?
From here we can see the rest of the development, good girl received unfathomably evil powers from the darkness, still tries to be a decent person with them.
Is in love with her BFF (that she assumes on probability alone is as straight as an arrow), but for now is comfortable with the shoujo-ai friendzone, complicated even further by how she is the daughter of the guy who is supposed to kill her just cause of who her deadbeat dad turned out to be.
Said BFF's father is stuck in a moral dilemma about slaying the girl and ending the bloodline of the darkness once and for all, because she might not turn evil, but even so any descendants she might leave may not resist the corruption so easily.
Hero's daughter sees her dad as basically being a stranger to her, having been away for most of her life, she knows him more through the stories told of him than actual experience of him as a father, her dad wants to try and make it right, only for this BS to pop up.
Eventually other events start to happen that lead to a bad for Lily, through a series of tragedies she ends up sinking fully into her role as the dark queen and sleeping with a lot of the female creatures at her command as well as raping captured female adventurers.
It's not just because she was destined to be evil by her bloodline, nor was it just that the right individuals assumed she would be evil, but because seeming every force the universe had conspired to make her go down that path.
The end is supposed to be surprising since the story as a whole mixes serious drama and horror with more lighthearted elements of comedy and slice of life. The story has it's highs and it's lows, but it isn't the story of the game itself.
The true story is you as the reincarnation of the hero's daughter as she sets out to slay the dark queen and finally put an end to all the wickedness, and you are doing it in a world where the queen has already won.
humans are slaves and close to dying out, the goal of the heroine is to beat the dark queen, and use her soul to go back in time to prevent everything that occurred, for with the two souls time itself can be redirected. Of course the dark queen Lillith wants the heroine's soul for the same purpose, not to further her goal by conquering the past, but also undoing what had gone wrong.
There is a lot of yuri and romance on each end of the tale, past and present, good and evil, freedom and fate.