My worst logic ever.
NOTE: You will need an image of the new Eeveelution cycle to get this.
Ok, Remember how Ninfia/Syleveon was recently revealed?
Did anyone see the image Eeveelution cycle?
It goes like this.
Look at the Pattern.
(Water)Advantage = Disadvantage(Fire)
(Phychic)Disadvantage = Advantage(Dark)
(Ice)Advantage = Disadvantage(Grass)
Now, The question is, What is the disadvantage of Electric types?
That's possibly your answer to Ninfia's type.
Also, I've recently seen a video. Ninfia was using Swift and some sort of Fire attack.
My logic could be wrong.
SonicLife is my name, And Burning way past cool is my game!