Elma and The 12th Doctor

A random idea that come to my mind at midnight:

One day, after her shift, Elma, the dragon of the Harmony faction, sees how the city where she lives, Tokyo, is invaded by metallic nightmares, coming from a hole in the sky, Elma tries to defend the city and the humans that inhabit it, but she is quickly overwhelmed by the advanced technology and the great number of them.

Those beings shoot death lazers at every human they see, the blue dragon tries to stand against the lasers but each hit burns with a force she has never felt before, she feels as with each hit, her life vanishes, she falls to the ground, closing her eyes....

But suddenly a blue box appears in the sky, and in the blink of an eye, the alien invaders are defeated. Elma watches as that British phone box disappears into thin air.

Thanks to the intervention of that blue box, she survived and the rest of the humans where safe... But, since that day, she asks herself the same question, what were those metallic beings? But above all, WHO was that old man in the blue box?