This got mentioned in a response to the last post; Sahiim’s origin I think had been covered here years ago, but I also would love to talk about it again since I have more thoughts about it now. Under a cut since it might get long.
Before meeting Primus, Sahiim had once been a human living in Desik, the more arid part of the planet this portion of the headworld takes place in. This region also had the greatest concentration of death and undeath god-like entities since the climate was perfect for mummification.
One of the entities has several of these undead communities under their reign, which a living mortal can enter if they act as an apprentice to an undead- wherein at the end of it, they too turn undead and join them. Sahiim had opted to join the Raasi, which are more of a lich-like community that are often sent to the realm between the living and the dead to make sure nothing passes over that should not (mainly evil spirits, the ghosts of entities that still have some sort of beef with the living, etc.)
Raasi tend to be viewed as very good, since they keep the ghosts of the dead from bothering the living. This, alongside the promise of power that was greater than most of the other undead communities, drew her in. However, at the end of her apprenticeship it was clear that not everything was how it had been described initially. For one, she no longer was human in any shape or form, now turned into a beast of burden, the other was that she would be working alongside another entity that tends to act as guardians regarding the realm of the living and dead.
The one she was paired with not only was controlling, but also had expressed interest in spiriting her off at some point to be partnered with them forever.
She hates this, and quickly becomes disillusioned to her new ‘career’ and existence as an undead. At one point Primus comes into the picture when he gets turned undead by a strange artifact. The guardian and her are drawn to the surge of power that occurred, thinking that something had jumped across the realm between the living and dead - or there was an unauthorized ascension to lichdom.
They confront him, and immediately a newly undead Primus slams the guardian into another dimension on accident and Sahiim suddenly finds herself free. From there on is where the two team up since Primus is not supposed to exist and Sahiim is not supposed to be without a guardian (it has to do with reigning in a Raasi’s power, keeping them from letting their abilities get to their head and doing anything heinous.) So they both are on the run from some sort of undead law.
Admittedly I had been thinking of rewriting or completely redoing Sahiim’s design and story since my ideas for this duo have changed a lot since they were made about three years back, but horse-lady is still fun to think about every so often.