ThePrelate

I would go with either this one (it does seem quite plausible, since the game states Yun isolate themselves from the world and are masters of art), the one stating them breeding with Gon males (since, well Asian mythology) or with the one that they bloom. Like, take some flower (lotus for example), make it 1000x bigger and when it blooms, a Yun comes out. Have fun with mental pictures.