So I noticed in the beginning, she summoned a dragon to kill everyone in the tower. Then, I noticed that in the later chapters, it said that she could only be killed by a dragon or the son of the demon king. So why didn’t she just use her powers to kill herself?
Because what she summons are spirits and souls, they use power because of her power, so she can't use it to kill herself, at least that's what I undertood. And also she doesn't think she's strong enough to break that body completelly which is why she needs someone stronger than her.
So I noticed in the beginning, she summoned a dragon to kill everyone in the tower. Then, I noticed that in the later chapters, it said that she could only be killed by a dragon or the son of the demon king. So why didn’t she just use her powers to kill herself?