[RPG] Do successive castings of Death Knell stack

pathfinder-1espells

Death Knell is a spell that among other things grant a temporary +1 increase to caster level.

I have seen different answers and questions here that seem to assume this spell stacks with itself.

Are they right or wrong?

Best Answer

No, it doesn't stack

This has been answered in a FAQ:

Temporary Hit Points: Do temporary hit point from the same source stack?

No. Generally, effects do not stack if they are from the same source (Core Rulebook page 208, Combining Magical Effects). Although temporary hit points are not a "bonus," the principle still applies.

This prevents a creature with energy drain (which grants the creature 5 temporary hit points when used) from draining an entire village of 100 people in order to gain 500 temporary hit points before the PCs arrive to fight it.

Temporary hit points from different sources (such as an aid spell, a use of energy drain, and a vampiric touch spell) still stack with each other.

—Pathfinder Design Team, September 2013

This includes the spell Death Knell, spell-like abilities that cast Death Knell, wands of Death Knell, and magic items that have the effects of Death Knell.

Although the FAQ is about temporary hit points, the principle is that bonus from the same source should not stack, as described on the Core Rulebook, under Combining Magical Effects.

Spells that provide bonuses or penalties on attack rolls, damage rolls, saving throws, and other attributes usually do not stack with themselves. More generally, two bonuses of the same type don't stack even if they come from different spells (or from effects other than spells; see Bonus Types, above).

Even when an effect is not labelled as a "bonus", if the effect increases it, it is gaining a bonus. Just like the spell grants you bonus temporary hit points (normally you have 0).