Is using the Consume Life power of the Twilight Sage an evil act, or are the rules silent about it?

Question

While building one of my Pathfinder Society characters, I was thinking about making an Arcanist and applying the Twilight Sage archetype. One of its abilities reads as follows:

Consume Life (Su)

By wresting a soul from life to death, a twilight sage gains a slightly deeper understanding of mortality, fueling her curiosity and eldritch power. As a full-round action, she can consume the life energy of a helpless living creature, killing it.

This creature must have 2 or more Hit Dice and be below 0 hit points. The twilight sage adds 2 points to her arcane reservoir if the creature’s Hit Dice equaled or exceeded the sage’s character level, or 1 point if the creature’s Hit Dice equaled at least 1/2 her character level.

This ability is a death effect.

This ability replaces consume spells.

This ability is a lot better than Consume Spells, the thing that Arcanists usually have, because it is not limited by its uses per day. After every combat, there are usually some helpless creatures on the ground, and this ability can be safely used to finish them.

However, Pathfinder Society forbids playing evil characters, and my GM told me that committing 2 evil acts in one scenario is going to shift me on the alignment axes towards being evil, which automatically expels me from Pathfinder Society.

I am afraid that using Consume Lift might be an evil act (after all, it's about killing a helpless living creature!), and hence this Archetype is going to be even less useful than Consume Spells because I am going to only be able to use it twice per adventure. I want to know if it is so by the rules.

Please, abstain from sharing your opinions and GM rulings. I know that adventurers routinely kill goblins and that it's not considered an evil act by my GM. I'd like to see an answer about actually finishing helpless creatures, an answer that cites rules and is based on said rules.

Answer 1

It is not an evil act, but it isn't good either

The ability doesn't mention anything about it being an evil act, only that it is a death effect, and those are allowed normally on PFS games. Also keep in mind that casting [evil] spells are not automatically evil acts on PFS either but that depends on how the spell is being used, as explained by James Jacobs. Though the final decision is up to your GM, he is advised to warn you that you just did an evil act and that there will be consequences if you keep that up (according to the manual, page 14).

The ability is no different from a magical coup-de-grace and that action isn't considered an evil act either. The ability also doesn't described that you actually consume the soul, despite the ability's name, which was confirme by a developer:

In fact, the idea is that you watch it go about its normal way and study the results. Macabre, but a step up from daemonic soul-sipping. You're basically killing it in a controlled environment. Y'know, for science.

Yeah, still really not a Good thing to do.

If used to finish off an enemy and activate your abilities, that's fine, it's a morally grey act, but if used to kill an innocent just so you can activate your abilities, the GM should warn you at first, then apply an alignment shift towards evil if necessary. Keep in mind that a character who becomes of evil alignment will be marked as "dead" on the chronicle sheet.

Answer 2

This is out of the Pathfinder Society Organized Play book:

Although in regular play poison use carries with it a legacy rule stating that poison use is an evil act, for the sake of Pathfinder Society Organized Play, using poison is no more evil than casting fireball.

I bring this up as it sets a precedent that what may be evil in normal play may NOT be evil in PFS.

I read through the Pathfinder Society Organized Play, the PFS Character Creation Guide, the PFS Primer, and the PFS Field Guide and none of them stated what an "Evil act" was. The closest was that quote above. All they say is that you are not allowed to play evil aligned characters. I will append that there may have been erratas to those books that added something, but I am basing this answer off the material I have.

With that said, I will refer you to another question very similar to this one asked on SE: Is Coup de grace on sleeping opponents an evil act?

tl:dr Not necessarily. It depends on the circumstances. Is said creature an enemy combatant that was knocked unconscious in your attempt to defend yourself? It would fall into the neutral territory of actions. Not good, not evil. Bringing lawbreakers to justice is not on the good/evil axis, its on the law/chaos axis.

Answer 3

No, in Pathfinder Society organized play, Consume Life is not an evil act.

Originally I'd say yes.

Even though the description of Consume Life doesn't mention anything in that regard, the effect of the ability is very similar to the Death Knell spell, which has an [evil] descriptor, and casting evil spells is considered to be an evil act.

From Descriptors, under "Additional Information on the Evil Descriptor"

Casting an evil spell is an evil act, but for most characters simply casting such a spell once isn’t enough to change her alignment; this only occurs if the spell is used for a truly abhorrent act, or if the caster established a pattern of casting evil spells over a long period.

The premise of the answer is as follows:

1. Killing a helpless enemy is not an evil act in itself, as answered in the linked question.
2. There is no exhaustive list of "evil acts" in Pathfinder, and, in fact, there cannot possibly be one by the very nature of the game, so we have to extrapolate in many cases.
3. Consume Life special ability is extremely similar to Death Knell spell: it targets a creature below 0 HP, it draws its life force out, it instantly kills the target, and it benefits the user (albeit in slightly different ways).
4. Death Knell is an evil spell and says so in the descriptor.
5. Casting evil spells is a known evil act that will change your alignment over time.

Therefore, using this ability should count as an evil act.

Further, this forum post by Jacob James (Creative Director at Paizo) re Infernal Healing spell use specifically says that it is entirely up to GM to decide how long does it take for character to change alignment, be it one, ten or thousand castings.

However.

There is a rule that I originally missed that renders the whole comparison moot. There is a specific exemption for Pathfinder Society saying that casting spells with [evil] descriptor is not an evil act in itself. So, given this, casting Death Knell, and, by extension, using Consume Life is not an evil act.