Verse:Mwail/Ròdh Xa̱y
(Modern Standard Thean) [Given name TBD] Xay¹¹, reverentially referred to as Naa¹³ Xay¹¹ ('Lady Xay¹¹') by her worshippers, was an Old Thean xenharmonicist composer and entrepreneur. She was deified posthumously and is worshipped by many ethnic Theans to this day.
[I don't know if she will be Thean...]
Life
Xay¹¹ was born into a technological world much like ours. She gained wide appeal within the Angaian [what age?] xenharmonic community for her compositions, approach to xenharmony, and various other accomplishments. Xay¹¹ was murdered at the age of 30.
Growth of the Lady Xay¹¹ cult
After Xay¹¹'s death, climate change caused most of the existing Internet infrastructure to submerge underwater, causing most data online to be lost. Thus historical sources from her lifetime are scant and the first available sources are by her acquaintances relying on their memory. Many of these people apparently had supernatural experiences involving her.
In the first few centuries after Xay¹¹'s death, oral tradition played a big role in developing and maintaining the folk religious material about Xay¹¹
Divine attributes
Lady Xay¹¹ is a goddess of creativity, wisdom, and craftiness. Her allegedly unjust death led her to being regarded as a deity of justice able to avenge other victims of injustices (according to post-apocalyptic Thean beliefs, such a death in addition to being a great figure during one's lifetime boosts one's spirit's power as a posthumous god).
In-universe scholarship
The only scholarly consensus about Xay¹¹ is that a woman named [given name] Xay¹¹ existed, that she was a composer, and that she was murdered or executed. Detailed reconstructions of her life and work are an area of debate. Due to the lack of sources from her life, a minority of Angaian historians posit that Xay¹¹ is a purely mythical figure.