Oliva sighed heavily, leaning forward, "You would have also seen how they fought themselves, and didn't attack you. If you had known what they were, Ren, would you have become friends with them? You seem to underestimate the value of feelings" She shifted, studying Ren. 

"They stopped because they didn't want to hurt you. You can't imagine how hard that would have been for them, no one could. They aren't what the demon that spawned them, wants them to be. Because they are human. They feel, and right now, Lorenzo is probably feeling better then Cassandra. She took up her blade, knowing what it would cost her, to protect you and Kiddo. Everything she did, she did because she cared. Why should we have told you what they are? You just would have judged them, and shunned them-Like you are doing now. Would I have liked you to bond some more before this happened? Yes. But you can't change what is. They can't change what they are, Ren. But they can decide what they do" 

She sighed. "They were born to a human mother. While Cassandra was raised by their m other, Lorenzo was sent away. I"m not even sure their mother knew she had had twins. They received spirit wounds off each other, I would imagine. I'm more then sure neither of them knew what they were for a while. I know Cassandra didn't find out until she came home to find her mother, and the only father she has ever known slaughtered. I was there, banishing the demon with others, but we came too late to save them. That's why I'm teaching them. And you. Their abilities awaken when they draw their swords. it holds their flames. As for what can stop them, well....their human side, really. Their feelings. I imagine you've hurt them, but not trusting them. They obviously felt like they could trust you, showing themselves to protect you. I hope they weren't wrong in that trust" 

She rose, gathering her things. "That's all Ren. You can go"