Stutter caster

[Anthrowhale]

Minor quibble: the mother cyst spells also need to target something living. 

Tweaked.

The Necrotic Cyst line requires the Mother Cyst feat to cast,

For most casters, that is correct.  For Stutter caster, the mother cyst is a focus, which is a component, which can be stripped by Supernatural Spell. 

and I don't see it on your list. 

I don't follow. 

Also, as a form of mental control, it's blocked by Protection from Evil despite not being Mind Effecting.

That appears correct---I didn't realize P from E has such a blanket statement.  That's cool---it makes it stronger than Mind Blank in some ways. 

[linklord231]

I meant that I don't see Mother Cyst on your list of feats. 
Even though you strip the component/foci off, you still need the feat to cast any of the Cyst line because of what the Mother Cyst feat says:

Normal:  A creature without this feat cannot cast Necrotic Cyst spells.

[ariasderros]

I meant that I don't see Mother Cyst on your list of feats. 
Even though you strip the component/foci off, you still need the feat to cast any of the Cyst line because of what the Mother Cyst feat says:

Normal:  A creature without this feat cannot cast Necrotic Cyst spells.

Stutter doesn't need to cast it. Stutter emulates it with a Wish.

[Anthrowhale]

Stutter doesn't need to cast it. Stutter emulates it with a Wish.

Although Limited Wish would work, I was imagining using supernatural deep in a recursively nested twin to guarantee success at high levels.

I meant that I don't see Mother Cyst on your list of feats. 
Even though you strip the component/foci off, you still need the feat to cast any of the Cyst line because of what the Mother Cyst feat says:

Normal:  A creature without this feat cannot cast Necrotic Cyst spells.

I think it's ambiguous how to interpret this clause in this context.  Learning and memorizing necrotic spells is clearly not forbidden, but casting might be.   Is this a reiteration that you can't normally cast a spell without it's focus or something else?  To settle it, you need to look at the spell itself which is the primary source for the spell.  The spell states that the mother cyst is a focus. 

[linklord231]

The general rule is "you can't cast spells that require a Focus without that Focus."  You overcome this by removing the Focus requirement.  But a more specific rule is "you can't cast Necrotic Cyst spells without the Mother Cyst feat," and you don't have a specific rule that bypasses this. 

But, the whole thing is rather moot anyway since you could still emulate it with other spells, and Prot Evil still works. 

[PlzBreakMyCampaign]

I agree that Mother Cyst feat is indeed needed to cast the spell. Yes its an interpretation, but I think I just don't think spell emulation is specific enough.

Its the one reason I've never been that into the necrotic focus spells. But hey, you're a T1 caster so just DCFS yourself after casting.

[Anthrowhale]

a more specific rule is

Whether Supernatural Spell or the Mother Cyst feat are more specific is ambiguous to me as they are both exceptions.

The Occam's Razor explanation for why you can not cast a Necrotic spell without a Mother Cyst is the use of the Mother Cyst as a focus in the casting.  Generally, I'd suggest going with the simplest explanation in an ambiguous explanation, but any DM is free to imagine other explanations and apply them.  In particular, always choosing the interpretation which minimizes the power of an overpowerful build does have some appeal.