Galaxia is most interesting as someone who started down her path to do good, to prove herself, to be the savior, but then as things started to go wrong she found the wrong so much more satisfying. Cruelty tastes so good on her tongue, others’ pain is so delicious in a way that their gratitude never was. She could never be the most good, the most pure, but she can still be the greatest, she can cause harm so vast that her name will live on for centuries, whispered in fear even in the furthest corners of the universe. 

Having her ~controlled by chaos~ is a cop out. If she has to take it into herself, let her realize she can work with it, that she can use it. It is her tool, rather than the other way around.