I'm anticipating rage next week. The Acolyte seems to be going into another past episode (as shown by the end of E06, and E03 and E07 have the same director) - I have a hunch that Mae actually died in the past narrative and Osha brought her back to life by tapping into the dark side of the Force and the trauma of seeing everyone in her coven burn. Sol knows this and covered it up. It's also why Osha was later separated from the Jedi order.

Basically my theory is that Osha becomes the sith master, Darth Plagueis, and later becomes the teacher of Darth Sideous. Sideous tells Anakin:

Darth Plagueis was a Dark Lord of the Sith so powerful and so wise, he could use the Force to influence the midi-chlorians to create life. He had such a knowledge of the dark side, he could even keep the ones he cared about from dying.

All the s are going to be so upset that the one who taught the OT Emperor was a queer black NB person.