The Mirror...

Mira is a descendant of The Mirror. The Mirror is a millennias old kingdom, who have been protecting the world from The Shard.
The Shard has been The Mirror's arch enemy for over 3 million years, which was when The Shard broke off from The Mirror and it's ways...The Shard's main purpose is to annihilate The Mirror, and all mankind.
The Mirror has been looking for the heir to their throne ever since The Shard stole the child and dropped it somewhere in a distant dimension...on the planet Earth.
Mira is that heir...If only she knew...