My affinity would be "The Void" which takes the form of darkness. It is named "the Void" because it is a metaphor for the void in which everything came from, & since everything came from the void it can imitate anything from it. I mainly use it to manipulate darkness in various ways but also mimic other forms of energy but in dark forms i.e. dark fire, lightning, etc.
I would use my qi to enhance my mind & body to supernatural levels (type II). I would also create Iron Rings using my very life-force making them a weapon then can always come back as long as my life-force exists.
My qi-enhanced physiology I would live long enough to become an empty hand fighter on supernaturally levels. With my combat being mixed with qi my strikes would be deadly being able to effect energy, strict vital points, strike from a distance, etc. & I would use qi to enhance my mind, I would qi-based psychic abilities which would afford my esp, telekinesis, teleportation, etc. I would also learn to manifest my astral form on the physical plane. I can manifest it;
Partially-
Or fully-
My astral form is something I can freely manipulate:
I would also learned to use my chi to transform my being into a more powerful version of myself for a time.
My vile qi is unnatural & gives me an unnatural connection to dark forces & beings such as zombies, darklings, etc. But my authority could be thwarted by various monster kings. With that being said I spend decades hunting them & killing them.
I would become a mighty King of Monsters after consuming a Kijin, Asura, Dragon, & kind of the underworld. I would aquire their natural traits but in human form such as unnatural physical abilities (type 3 supernatural), claws, draconic breath, prehensile tongue, shapeshifting, etc. My qi would become transcendent & my authority over the creatures & realms of darkness will be unquestioned. My base human form (if you can call it that will mutate as a result of my qi
& my true form will be more draconic & asura like