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.