(Okae, so Ying Yue comes from a long line of "shamen" I guess you could call them, who are well known for providing medicines and ancient healing practices around the Inferno. People from all over and miles away look to them (the collective) for their skill and wisdom in the ancient arts, from simple colds to trying to reverse a certain curse. People know the Jiang family very well, and they are all highly respected.
On top of working in medicine though, they also dabble in potions. Potions that Do Things™️. And this is something that has always interested Ying Yue, but unfortunately for them, their family is very strict, and very traditional, and women are not allowed to work with potions. They make medicines and nurse patients, and that's it. But, ofc, Ying Yue has never really felt "lady" to begin with, and so, feeling entitled and using that fact as good and reasonable excuse, they worked in secret, and dabbled in their own potion making, experimenting with everything they could get their hands on
Their first few successful potions were simple things, dumb things really. One made your tongue glow for a little while, another made your voice sound like you inhaled helium, and just silly things like that, but after getting caught and ending up in a lot of trouble, Ying Yue sought to prove to their family that a woman could make a potion just as powerful as a man could, and so they gathered the rarest and most powerful ingredients they could find and worked to create their Ultimate Potion™️, one that would change warpa society forever
But they misjudged themself, and ended up really hurting themself when they tested this "masterpiece"
The potion cursed them with a parasitic plant which began consuming their body from the inside out
And they were nearly lost, had it not been for the aid of their family
Still, even with their family's efforts, the curse remains, and Ying Yue is left with a horrible, chronic cough wherein they'll cough up blossoms and blood, which causes them a lot of pain in general, especially when it comes to speaking
Because of this, Ying Yue chooses to be mute, and relies on sign language, writing, and other forms of communication
They still dabble in potion making, and are trying to craft a cure for their own curse, but they no longer work with their family, outcast after the events and their refusal to stop trying)