User blog comment:KodachiZero/Hatsune Miku Collaboration (Translated)/@comment-25509860-20141007124612

They should've release all 6 Vocaloids...

-Miku = Earth

-Rin & Len = Thunder (together as one unit)

-Luka = Dark

-KAITO = Water

-MEIKO = Fire

but I'm still glad they did release Miku! Yays~