Referring to the last chapter. Ancient Powers, Peacebreaker and (Y/N) have only a portion of these powers and you will discover in the following chapters.

The Ancient Power was created from Deep Magic and every elemental master or users of any kind of power has it.

(Y/N) doesn't possess all the elements of this power. It possesses only a few of them and you will discover in the following chapters. She can be defeated and killed, but it takes effort. But it won't happen... or maybe??

(Y/N) isn't that powerful and no, it is not in something like a deity that is ultra powerful. She only possesses a sliver of this power and does not possess absolute power. 

And no, she doesn't have all the elemental powers we've come to know. She only has the powers of her defenders, Kai, Cole, Jay and Zane.