User blog comment:Gundam Legilis/Cinder's motivation/@comment-11188061-20151215005928/@comment-11188061-20151215023301

But it is still entirely possible that Cinder is a Maiden, even if there's a lower chance that she may be a Fall Maiden. Her song indicated that she is possibly a natural born Maiden, but was groomed to die so that her powers may be passed on to a specific individual; to be preserved under a certain family or organization.

It is also entirely possible that Cinder did die during the process, or at the very least come very close to it, but somehow she survived. Remember that Atlas has been conducting experiments to extract Aura from a person, and while we thought before this Episode that they're trying to mass produce artificial Huntsmen, in truth they are actually trying to extract the power of the Maidens. Idealy if they can find a method to extract a Maiden's power without killing the host, or at least extract and transfer it to a chosen taregt, then they will be able to control who is next in line to become a Maiden. So who's to say that Cinder isn't a product of those experiments?

"You can't have my life, I'm not your sacrifice. You can try, but I'm free, And you won't conquer me."

Cinder's back for revenge. My theory can be off but I'll believe this motivation at least.