I've noticed that while played as a succubus, punching people will occasionally set things on fire. I think it's the sweat. After working up a sweat from a good brawl, a succubus ends up covered in a layer of sweat. Which is hot enough to set fire to things it comes in contact with. Spitting on people also sets things on fire.
I think it's this part of raws
[HOMEOTHERM:10075]
[FIXED_TEMP:10075]
[SELECT_MATERIAL:ALL]
[MULTIPLY_VALUE:3]
[COLDDAM_POINT:NONE]
[HEATDAM_POINT:NONE]
[IGNITE_POINT:NONE]
[IF_EXISTS_SET_MELTING_POINT:25000]
[IF_EXISTS_SET_BOILING_POINT:30000]
This lets them live in lava. It means they'll stay at a comfy room temperature and it'll take a very high temperature to melt or boil them. Unfortunately, a quirk of dwarven physics means that if a material is forced to be created in a particular state (such as liquid) then it'll take on the nearest temperature it can exist in that state. It's an effect used elsewhere in Masterwork for stuff like freeze attacks. So succubi aren't supposed to melt at any mortal temperature but blood, sweat, and tears are technically in a molten state so they must be insanely hot.
Don't have a quick solution for either meph or boltgun. Removing the melting point changes does mean I can't incinerate people by spitting on them but will might mean bad things if I take a lava bath. I know there's some funny behavior when it comes to netherbark and glass submerged in lava, which are normally magma-proof.
Yeah I noticed that part when I desperately tried to edit the raws to either make them not exude pure magma, but alas, I am not meph, they do also have the fireimmune super token right above that area so maybe that'll keep em safe?
But maybe I'll mess around with that part, removing the boiling point, the fixed temp is pretty normal, and if I have to sacrifice succubi immunity to lava just to have them not be some rediculous death force, I'll gladly take the sacrifice...My human adventurers need their revenge! The bastards have taken over most of their lands with no issues!