Can Life Link be used to have multiple bonds active on one creature?

Question

Oracle (Life Mystery) and Shaman (Life Spirit) can both gain access to the ability Life Link:

Life Link (Su): As a standard action, you may create a bond between yourself and another creature. Each round at the start of your turn, if the bonded creature is wounded for 5 or more hit points below its maximum hit points, it heals 5 hit points and you take 5 hit points of damage. You may have one bond active per oracle level. This bond continues until the bonded creature dies, you die, the distance between you and the other creature exceeds medium range, or you end it as an immediate action (if you have multiple bonds active, you may end as many as you want as part of the same immediate action).

Can this be used to have multiple bonds on a single creature? For example, at 2nd level the Oracle/Shaman can create two bonds. Obviously these can be placed on two separate creatures to heal each for 5, but could both bonds be placed on a single creature to heal that one for 10?

If no, why not?

If yes, how does that work when the bonded creature has taken enough damage to trigger Life Link, but not enough for both bonds to heal? If, let's say, the bonded creature is at 15/20 HP, with two bonds active on it, would the Oracle : A) Heal the bonded creature for 5 HP and take 5 damage, or B) Heal the bonded creature for 5 HP and take 10 damage?

Finally, what if the character has access to both forms of Life Link (either via Oracle/Shaman multiclass or by the Oracle archetype Spirit Guide)? If the PC couldn't previously have multiple active bonds on a single creature, can it now (one from Oracle one from Shaman)? Also, same question as above about how it would heal in the 15/20 HP scenario.

Answer 1

By RAW, this effect stacks with itself, and can trigger multiple times at once.

The Combining Magic Effects section of the PFSRD talks a lot about how different spell effects stack, but one thing it never actually comes out and says is that identical spells with identical non-bonus effects do not stack. If it's the same effect in different strengths, it doesn't stack, or if it applies a typed bonus twice, it doesn't stack, but nothing I can find actually says "two identical non-bonus effects don't stack". Since the general rule is "Except in special cases, a spell does not affect the way another spell operates.", and there is no specific exception here, the effect can stack.

If an Oracle/Shaman has multiple bonds on one creature, then they trigger in sequence until the target has less than 5 damage. From the Combining Magic Effects section:

Same Effect with Differing Results

The same spell can sometimes produce varying effects if applied to the same recipient more than once. Usually the last spell in the series trumps the others. None of the previous spells are actually removed or dispelled, but their effects become irrelevant while the final spell in the series lasts.

So, if your magic effect has some kind of variable logic in it, then it doesn't work if another simultaneous effect makes that logic invalid. To my knowledge, there is no RAW way to adjudicate multiple simultaneous triggers, but it doesn't much matter in this case. The rules say that you trigger each Link in turn, healing 5 HP and taking 5 damage, until either you run out of bonds or the target has less than 5 damage to heal.

It doesn't matter exactly where the Shaman/Oracle gains Life Link, or if they have multiple copies. Since all copies of Life Link have the same effect, they all fall under the same set of rules for combining effects.

One thing to note, though, is that this makes for poor playability. Given the other restrictions on stacking effects, it seems pretty clear that the intended behaviour is that identical effects from identical sources don't stack. The fact that this ability happens to fall in a gap that the rules don't totally cover seems more to me like a problem with the rules than an intended behaviour. In play, I wouldn't allow this kind of stacking. One Oracle/Shaman would be able to place only one Life Link on any particular target, in my games.

Answer 2

• Can the supernatural ability life link (possessed by some oracles and shamans) be used multiple times simultaneously on the same creature?

  Probably not. While the rules for Combining Magical Effects emphasize bonuses, the source of these rules makes it clear that these rules don't apply only to numeric bonuses but, instead, apply to any benefit that comes from an effect identical or extremely similar to an effect already present on the subject. In the case of the supernatural ability life link, this isn't even Same Effect More than Once in Different Strengths or Same Effect with Differing Results, but the same effect with the same result. Layering bonds does not combine for a cumulative effect.

  Pathfinder draws from the System Reference Document for dnd-3.5e for its Combining Magical Effects rules, and these earlier rules omit the examples from Pathfinder's predecessor's Player's Handbook (171-2) and examples would've made all this much clearer. I've no idea why Pathfinder opted not to include its own new examples which would've clarified this because the idea that a subject can be affected by an identical effect more than once still arises, albeit infrequently.

  Further, while Combining Magical Effects seems confined to spells, Special Abilities—in the same section as Combining Magical Effects—includes spell-like abilities and—relevant here—supernatural abilities like life link, and such abilities are like spells except…. So, for the same reason that a creature affected by a supernatural ability like the fly spell and affected by the actual spell fly does not benefit from, for instance, a doubled fly speed, a creature subject to more than one bond via life link from any source doesn't somehow get double the benefit.

• If the GM rules that one creature can be the subject of the supernatural ability life link multiple times simultaneously, what happens?

  Obviously, ask the GM. The Pathfinder rules as they are presented are vague enough for the GM to allow multiple bonds to be established on a lone creature, especially if players are unfamiliar with or unwilling to return to Pathfinder's source material. (That's not a criticism, by the way. I agree that Pathfinder should be self-contained without needing to reference other games, but in this case it is a spot in the rules that hasn't received much attention from developers since the game's release, relying exclusively on a different game from the turn of the century to make itself clear.)

  Were this GM to allow the bonds created by life link to combine for a cumulative effect, this GM would allow the effect's creator to create bonds on a lone creature that all triggered when the subject creature reached −5 hp, each bond consecutively—not, as the rules would otherwise demand, simultaneously—dealing the effect's creator 5 hp of damage and healing the affected creature of 5 hp of damage. (That is, having the −5 hp treshold become increasingly negative (−10 hp to deal and heal 10 hp, −15 to deal and heal 15 hp, etc.) would make the ability to combine the bonds for cumulative effect almost useless.)