Permanent Enlarge Person and Kitsune Shape

Question

The subject of this question is a Kitsune character under a permanent Enlarge Person spell. I have some difficulties to figure out how it will react with the two shape features of this character, which are the Kitsune Change Shape and the Fox Shape feat.

Kitsune Change Shape says:

Change Shape (Su): A kitsune can assume the appearance of a specific single human form of the same sex. The kitsune always takes this specific form when she uses this ability. A kitsune in human form cannot use her bite attack, but gains a +10 racial bonus on Disguise checks made to appear human. Changing shape is a standard action. This ability otherwise functions as alter self, except that the kitsune does not adjust her ability scores and can remain in this form indefinitely.

The Alter Self description says :

When you cast this spell, you can assume the form of any Small or Medium creature of the humanoid type.

For this one, I'm not sure this is RAW, but what seems to me the most logical is that the alter self effect would come first, resulting in a medium humanoid character and the enlarge person next, to give a large humanoid. Otherwise, the Change Shape would allow the character to ignore the enlarge person effect when taking a medium sized form.

The issue with the Fox Shape seems even more tricky as this one is not directly related to the initial size and implies to take the form of a tiny fox. Would it ignore the effect of the permanent spell, or would it result in a medium sized fox ? Or something else ?

Finally, if some of these transformations enter in conflict with the enlarge person effect, would there be an impact about the permanency ?

Answer 1

The kitsune is affected polymorph effects as if the kitsune were its size absent any size changing magic, even an enlarge person spell made permanent

The transmutation subschool polymorph, in part, says that "other spells that change your size have no effect on you while you are under the effects of a polymorph [subschool] spell" or effect. (That's buried, like, way deep in subschool description; it might take searching for it to find it.)

This typically means that when changing shape using a polymorph subschool effect, a creature changes shape as if it were its original size, no matter its current size due to ongoing magical effects, like an enlarge person spell affected by a permanency spell.

(Even spells with a duration of permanent can be dispelled and count as ongoing. For the kitsune to change its size category instantaneously—so that magic changes the kitsune's size then the magic ends yet the size change remains—the kitsune would have to do something like draw the 5 of diamonds from a harrow deck of many things.)

Thus a kitsune's supernatural ability change shape that "otherwise function as alter self"—a spell of the polymorph subschool—functions as written no matter how big or how little size changing magic has made the kitsune. Likewise, the Fox Shape feat's effect "functions as beast shape II," also a spell of polymorph subschool, therefore ignoring any size changing magic present on the kitsune.

Either way, when the kitsune ends the supernatural ability change shape or exits fox shape, the kitsune will return to its normal form on which is present the ongoing (i.e. permanent) enlarge person spell and continue to benefit from it for the duration.

Were this a normal enlarge person spell, this GM would count time spent in a different shape toward the enlarge person spell's duration in the kitsune's original shape—fortunately for the kitsune in the question, this isn't an issue.

Answer 2

Enlarge Person and Kitsune's Change Shape/Fox Shape will not stack

Change Shape works as Alter Self, as such, you can turn into a single human-looking form. It is a transmutation(polymorph) effect, while Enlarge Person is a size-changing effect.

Fox Shape feat works as Beast Shape II, also a transmutation (polymorph) effect, with the exceptions noted in the ability (a single fox form), otherwise it follows all the rules noted in the spell, as such, it cannot stack with Alter Self, ever. Whatever effect is applied last will take precedence over the previous, if you so choose to, but you cannot have two polymorph effects on your character at the same time.

You can only be affected by one polymorph spell at a time. If a new polymorph spell is cast on you (or you activate a polymorph effect, such as wild shape), you can decide whether or not to allow it to affect you, taking the place of the old spell. In addition, other spells that change your size have no effect on you while you are under the effects of a polymorph spell.

However, note that size-changing effects are negated while under a polymorph effect. Even though you are under the (permanent) Enlarge Person effect, the size-changing bonuses are lost when under a transmutation (polymorph) effect. The size-changing spell effect won't be dispelled, you simply won't benefit from it.

So, if you are in your Fox Shape form and become targeted by Enlarge Person, you will not become a larger fox, not because you are not a valid target for Enlarge Person, but because polymorph effects won't allow other size-changing effects to work. Same goes if you use your Change Shape ability, you will not become a larger human, but become a medium-sized human normally.

You cannot combine Fox Shape with Change Shape either, as both are polymorph effects.

You should note that while in a new form, your creature type doesn't change, so your kitsune will always be a humanoid (kitsune) creature, unless something else specifically calls out that your creature type has changed, as noted under this answer.