Does Ki pool Stack from multiple sources in pathfinder? I'm looking to multiclass monk/ninja and want to know if I can combine those two ki pools into one.
Whether or not the ki pools stack depends on the sources.
And some of them "stack" multiple pools, but get a smaller total size.
By default, even if two abilities or class features have the same name, they do not stack. If something does stack, then it must say so in the ability description. There are multiple possibilities of stacking ki pools in Pathfinder; they only stack if at least one specifically says they stack.
- The Ninja's ki pool (level 2+) stacks with other ki pools to form a shared pool. Yay! However, for calculating the pool size, you only include one ability score modifier.
If the ninja possesses levels in another class that grants points to a ki pool, ninja levels stack with the levels of that class to determine the total number of ki points in the combined pool, but only one ability score modifier is added to the total. The choice of which score to use is made when the second class ability is gained, and once made, the choice is set. The ninja can now use ki points from this pool to power the abilities of every class she possesses that grants a ki pool.
The Monk's ki pool (level 4+) does not mention stacking.
The unchained Monk's ki pool (level 3+) does not mention stacking either.
The Enlightened Paladin archetype gets a ki pool at level 4 that functions like the monk ability, which does not mention stacking, so it does not stack either.
The Sacred Fist Warpriest archetype also gains a monk-like ki pool at level 7. No stacking.
The Ki Pool rogue talent is bizarre. It gives a ki pool feature similar to the ninja's feature, yet it does not scale with level. It "stacks" in the sense that you share it between classes, but the size of the pool doesn't actually increase. I explain this below.
Here are some examples of how different combinations stack with each other. Below are some class combinations that can share ki pools between class features.
- Ninja (Lvl 2+) / Monk (Lvl 4+). Or, Ninja (Lvl 2+) / Unchained Monk (Lvl 3+). The pools stack, and scale with both class levels:
Total ki points = (Ninja level + Monk level)/2 + (either Cha or Wis modifier)
- Ninja (Lvl 2+) / Enlightened Paladin (Lvl 4+). The pools stack, and scale with both class levels:
Total ki points = (Ninja level + Paladin level)/2 + (Cha modifier)
- Ninja (Lvl 2+) / Sacred Fist (Lvl 7+). The pools stack, and scale with both class levels:
Total ki points = (Ninja level + Warpriest level - 3)/2 + (either Cha or Wis modifier)
So far, so good. Now to explain this rogue talent...
- Monk (Lvl 4+) and Ki Pool Rogue talent. You share the pool between both classes, but you only count the Wisdom modifier once, and so the pool size only increases with monk level:
Total ki points = (Monk level)/2 + (Wis modifier)
- Ninja (Lvl 2+) and Ki Pool Rogue talent. Once again, the pools are shared, but only increase with ninja level, so you don't actually gain any more points than a ninja would:
Total ki points = (Ninja level)/2 + (either Cha or Wis modifier)
Does that mean it's better to not stack?
That depends on the character build you want. If you have two sources of ki pool and neither of them stack, then you can consider them to be completely separate abilities. In other words, you have a tradeoff between:
One shared pool between classes, counting only one ability score modifier; or
Multiple separate pools, each including an ability score modifier.
For example, a Monk + Sacred Fist warpriest would have two completely separate ki pools. Each pool would include your Wisdom modifier and half of the corresponding class level. However, although they are both called "ki pool", they are completely separate; the points in your Sacred Fist's pool cannot be used for Monk abilities, and vice versa.
According to the Paizo FAQ, abilities gained from multiple sources don't stack unless they specifically say they stack.
The question is about Channel Energy, but it states a generalized point.
Channel Energy: If I have this ability from more than one class, do they stack? No—unless an ability specifically says it stacks with similar abilities (such as an assassin's sneak attack), or adds in some way based on the character's total class levels (such as improved uncanny dodge), the abilities don't stack and you have to use them separately. Therefore, cleric channeling doesn't stack with paladin channeling, necromancer channeling, oracle of life channeling, and so on.
So you'd basically get multiple separate Ki pools that each do different things.