So I've gotten to a point in my writing where I can share what passes for a plot point, and I want input about whether or not this would complicate an otherwise simple idea too much. @Suiisbestgirl, this is related to Muramasa so you might have the best input.
To make this as short as I can, Click to Toggle Spoiler
In one of the endings for the character Momohime, her soul gets fused with the spirit of a swordmaster, giving her all of his skills but causing her to lose her memories and become a wandering adventurer named Oboro. This is what my fic uses as its starting point. For sinister and horny reasons, Meiouki wants to use his spirit-draining rape powers to steal the swordmaster essence.
At this point, I could go one of two ways. One, Oboro remains Oboro. In this version, Meiouki's rape is extremely brutal, in the vein of Nightmare's scenes in the game (you know, innards being pulverized, bones snapping, the girls almost dying before being "saved" by having their insides replaced with demon organs. Two, Meiouki stealing the swordmaster's essence causes Oboro to revert to Momohime, restoring her memories partly or entirely. Technically the horror sex still happens to Oboro persona, but offscreen, and Momohime wouldn't remember it, so from her perspective she still has wild but much more enjoyable sex with her new oni master to start her life as a top of the line seedbed.
Which seems preferable? (The reason I don't want to include both sex scenes in full if Oboro's still happens offscreen in the second version is that they'd be very similar)
Addendum: I did think of one specific idea for the Momohime option to make it more distinct than just tone of sex scene: Momohime's memories return, but only up to the point where her family is attacked in a coup. Meiouki, surprised by his pity for her, takes advantage of her general ignorance to claim that she offered herself to him as a bride in return for an army to avenge her family. As a result, Momohime's end is basically Torahime but really really lewd.