so uh I have a theory about the mist twister. Which I think might help justify it's existence?
Particularly what it's based on, and what I think it might be the origin of in the HTTYD universe.
This is Wu and Wei, the Mist Twister attached to the main cast of The Nine Realms.
Mist Twisters are two-headed tidal class dragons, one head shoots fire, the other shoots water.
And in actual chinese myth, there is a two headed dragon, albeit with much different anatomy
Hong or Jiang, the Rainbow Dragon of chinese myth. It is considered aligned with Yin, as it controls water.
In real life, rainbows are created when light is refracted through water.
What is something that creates light? Fire.
one head of a mist twister shoots fire, the other shoots water, like I said earlier.
So, the Mist Twister is Hong, and I have reason to believe this, due to concept art.
The multi-colored tail fan!
Plus, since white is all the colors of light together, and black is the absence of light, it would make sense.
So, basically, the mist twister is Hong with much more realistic anatomy.