What happens in this situation with spell casting?
You have 5 level of sorcerer then take Red Mantis Assassin. Do the caster level stack for Illusion and Transmutation since they both use the same spell list?
I have this Sorcerer NPC that my players have interacted with. I want to add 3 levels of RMA to this NPC. Basically I have player interested in going into the RMA Prestige class and this would be a mentor.
So in the this example I have a level 5 sorcerer with 3 levels of RMA. Would Illusion and Transmutation spells cast be at 8th level CL. But if any other school would be cast at the Sorcerer CL.
You have 5 level of sorcerer then take Red Mantis Assassin. Do the caster level stack for Illusion and Transmutation since they both use the same spell list?
No. When using a red mantis spell slot, you cast as a red mantis of whatever CL your red mantis is. When using a sorcerer spell slot, you cast as a sorcerer of whatever CL your sorcerer is.
Sorcerer and Wizard both use the same spell list, but their CLs don't stack if you multiclass.
Red Mantis Assassins gain spell slots to cast RMA spells. The fact that those spells happen to be drawn from the sorcerer spell list doesn't let you stack them with sorcerer any more than you would be able to if you took levels in wizard. Compare to the Loremaster, which does not get any spell slots or spell lists of its own, but instead advances a class you had before.
Red Mantis Assassins gain spell slots to cast RMA spells. The fact that those spells happen to be drawn from the sorcerer spell list doesn't let you stack them with sorcerer any more than you would be able to if you took levels in wizard. Compare to the Loremaster, which does not get any spell slots or spell lists of its own, but instead advances a class you had before.
That's different animal entirely. You are talking spell casting progression which requires you to have casting in the first place. I'm just asking about CL since both classes cast of the same list. You wouldn't progress spell casting which does both more spells, great spell level and CL just the CL.
Here's my thing, I'm going to stack them as that just makes sense to me. I want to know if this could be RAW rule so I don't need to add it to my list of house rules. That way I don't need to print a new copy for my players. I just can't find anything one way or the other on this topic. People just saying "no" doesn't help in this situation because it's like me saying yes it does work by RAW. Anything showing it should be one way or the other suits me fine as all it means if I can reference the core books or my house rule document.
People just saying "no" doesn't help in this situation because it's like me saying yes it does work by RAW.
If you wanted to say it works this way, the burden is on you to cite the rules that say so.
A level 8 character with 5 levels of sorcerer and 3 levels of wizard does not cast at CL 8.
A level 8 character with 5 levels of sorcerer and 3 levels of red mantis assassin does not cast at CL 8.
Prestige class Definitions of Terms - "Caster Level: Generally equal to the number of class levels (see below) in a spellcasting class. Some prestige classes add caster levels to an existing class."
The fact that Red Mantis Assassin does not add caster levels to an existing class means you do not add those levels to existing levels of a spellcasting class to determine caster level.
Red Mantis Assassins gain spell slots to cast RMA spells. The fact that those spells happen to be drawn from the sorcerer spell list doesn't let you stack them with sorcerer any more than you would be able to if you took levels in wizard. Compare to the Loremaster, which does not get any spell slots or spell lists of its own, but instead advances a class you had before.That's different animal entirely. You are talking spell casting progression which requires you to have casting in the first place. I'm just asking about CL since both classes cast of the same list. You wouldn't progress spell casting which does both more spells, great spell level and CL just the CL.
No, it's the same thing. When you cast a spell, it's either a sorcerer spell or a RMA spell. It can't be both, because they have different spell slots and lists. If it's a sorcerer spell, it uses your sorcerer level. If it's a RMA spell, it uses your RMA level. Nothing says they stack, so they don't stack, any more than taking wizard levels would increase the caster level for your sorcerer spells.
If RMA had an ability which said "A RMA adds their level to the caster level of any illusion spell they cast", then there would be reason to consider stacking. But it doesn't. It's an entirely separate class which just so happens to have a mostly-overlapping spell list.
Just because a spell is on the spell list of two different casters that does not mean the caster levels stack. Each spell still only counts CL from one source. As an example if you multiclass wizards and sorcerers the CL's don't stack.
They had to make a PrC in 3.5 that would let you do so, but that class does not appear in PF. There have also been no rules changes in PF to allow spells to stack for the purpose of CL just because you multiclass.