Mistëa is maiarin spirit of rain. As being Maia of Rain, she serves both Manwe and Ulmo. Mistëa was able to combine power of sky and water to make rain. Her rain was create to cleanse and purify evil on Arda. She dwelled in the palace o Manwe, but she need to spend some time with Ulmo in waters, otherwise she will not be able to create rain. Mistëa is joyfull Ainur, happy and very active but little bit childish. Her title is Sky Dancer.
She has also sister - Nixë, maiarin spirit of Snow.
Mistëa - from quenya Mistë- means rain
Aerien - name given by Men, possibly from word Air