Bakkuttsing

Name: Bak Kut Tsing
A.k.a.: Báigǔjīng, Pák꜇ Kwat꜆ ꜀Tsing, Bakkuttsīng
Gender: Female (but can take on the physical form of a male)
Species: Skeleton demoness
Abilities: Shapeshifting, size manipulation, qinggong (remaining air-borne after jumping)
Goal: Obtain immortality

Bak Kut Tsing (Middle Chinese: 白骨精 (*bak kuət tsiɛŋ), literally "white bone/skeleton spirit/demon") is a shapeshifting skeleton demoness who resides in the mountains. She used to be a human who had gone on a quest for immortality. After ingesting what she thought to be the Punglai Elixir, she was presumed dead. However, several days later, she reawoke as a skeleton demoness with the ability to change her physical appearace, even to the extent of appearing as someone of a vastly different age and a man. She later found out that her lifespan is now much longer than a human's, and initially enjoyed it, but after many years passed, she decided that she was not satisfied with being mortal, and continues her search for immortality to this day. There is a rumour that immortality may be in the form of a certain kind of living being, and another states that it comes in the form of minerals. She just can't be sure which is right.

Her true form looks like a skeleton, although she almost always takes the form of a human, especially when going out. Bak Kut Tsing is a bit of a cunning, persistent trickster, and would try different means to attain her goal. However, she is also rather gullible despite her cunningness, and a mention of immortality would definitely catch her attention, and she would try to obtain it at all costs.

One of her interests is the anatomy of mouths (especially that of humans) and its role in vocalization, which she's taken her free time to learn about.

Backstory:
The first rumour she heard after becoming a demoness was that eating a monk by the name of Tang Sam Dzang, who was allegedly the reincarnation of a divine being, would grant her immortality. And it happened so that one day, Tang Sam Dzang and his disciples did in fact venture near the mountain she lives in. She decided to disguise herself as a young village girl to give poisonous fruits to Tang Sam Dzang and his gang, but the disciple Sun Ngu Kung the monkey king saw through her trickery and tried to kill her. She survived, and came back a second time, disguised as an old woman looking for her "lost daughter". Ngu Kung tried to kill her again, but she survived and returned a third time, now posing as an old man looking for his wife and daughter, and telepathically taunted Ngu Kung to kill her, as by this time Tang Sam Dzang was very displeased with Ngu Kung, for he doesn't know that the people Ngu Kung apparently killed were in fact a demon, and thought that perhaps the monk would get rid of Ngu Kung for "murdering the innocent". Ngu Kung finally beat her up a third time, this time causing major injury to Bak Kut Tsing, almost to the point of actually dying. She decided therefore to retreat for the time being, and look for another way or another time to obtain immortality...