She was a terror in her old world, too. That was her problem, she couldn't find anything that could kill her in battle, which is the only thing she wants to do. That's why Buddha sent her here.
We get a big clue in this chapter, too. Heroes have only ever fought monsters, and thus have some reservations about violence. She, on the other hand, is totally broken; we get to see her hugging the decapitated head of someone she killed because he said that she'll get to die in battle one day, too. It re-enforces something we've seen since chapter 1: she reacts to violence and battle with a deeply unsettling glee, so she's been catching everyone off guard because of it. The imps held the dwarf hostage, and she called their bluff because of her totally insane worldview where the best thing for him to do is die since he got captured.
It's an interesting twist on the usual isekai value mismatch, where more egalitarian and modern views on the value of life and people give the MC the ability to solve problems that the world can't. Instead, her totally insane desire to die fighting and the belief that everyone's trying to do that makes her unpredictable and dangerous in a way the monsters of the world have a hard time dealing with.