Let me be perfectly clear. I have no issue with violence or amorality. In fact, it can often be fulfilling to soak in the macabre. So even though I dislike this term, the only phrase I can think of to describe this manga is "senseless violence." There are fights, but they are quick and empty. There is pain and suffering, but it has no weight behind it. There is cruelty, but it has no impact because I'm not invested in the characters or the world.
The main character, Sena Kaito, is supposed to have been abused throughout his life, leaving him emotionally broken and unwilling to resist or even run away from his father. Yet as soon as he is reincarnated, he gains a sense of confidence and self-assurance out of nowhere. He adds nothing to the story, beyond being an outsider whom the reader can project themselves onto. And then he starts becoming emotionally attached to the Torture Princess, even though she treats him abusively. As for the Torture Princess: her supposed heartless sadism is undermined by splashes of empathy and kindness; trying to make her relatable ends up making her a weaker and less interesting character.