This story is based on the urban legend "1999 Earth Defense War". Any similarity is purely coincidental.
The main line of this story is UEC (United Earth Coalition) VS ? A??ī-Teyunī-Qān? O∶∶Sūr?? N (Holy Sky Empire Alliance)
(The unknown text above is based on the existing languages: Old Norse + Old English + Latvian independently created Tianyu)
Purpose: The radiance of humanity when facing a common enemy