Charley might appear cold and indifferent when she was still the so-called Sweet Death, but it was only because after the two became separated when they were still a kid.
Elissa came from a noble family, Mohon Family. But the world was as if playing with her when her parents were killed by their own family.
Elissa was helpless. She wasn't even in her teens at that time. She was too weak for revenge. She was the only daughter of her parents so she had nothing left to rely on. Despite that, she still wanted to avenge her parents.
That being said, she walked the path of assassination. And for her precious and only friend she had, she left her so that the other party wouldn't be implicated with her own problems.
Charley was furious. She wanted to help but her friend actually left her? She sought her friend Elissa but never saw her ever again.