Stormcaster and Born of the Three Thunders

[BalrogSamson]

I'm familiar with Stormcaster's synergy with Born of the Three Thunders. The common one I hear often is that the Thunderbolt ability stacks with Born of the Three Thunders providing two saves instead of just one. Which is gnarly and awesome.

However, what about this: would a Stormcaster's Storm Spell Power ability provide a +4 bonus to caster level if Born of the Three Thunders is applied to an electricity spell? Here's what the ability says (emphasis mine).

Storm Spell Power (Ex): You are truly skilled in the use of spells that wield the power of the stormy seas. Any spell you cast that has the air, electricity, sonic, or water descriptor is cast at +2 caster level.

Born of the Three Thunders adds the sonic descriptor to any electricity spell, among other things. Would this mean that a Lightning Bolt of the Three Thunders is cast at +4 caster level because the spell is both electricity and sonic. Or +2 because... because? Should I allow this or what? It's strong but seems like its intended and I can't find an argument against it...

 

[Dandu]

I'd argue it only applies one time.

I would invoke the "bonuses from the same source do not stack" rule.

 

[Empirate]

The operative word in the sentence you quoted is "or". The ability provides a fixed bonus to you if one of certain conditions is met: if any (i.e., at least one) of the mentioned descriptors apply, you get the bonus. If none apply, you don't. It's not implied anywhere that the bonus might be multiplied if multiple descriptors apply. Usually, WotC source material makes pretty sure to explicitly spell these things out.

As for this part: "It's strong but seems like its intended and I can't find an argument against it..." How does it seem like it's intended? If it were intended, it'd be spelled out. Arguments against are not needed; in fact, to me it looks like somebody first needs to come up with a compelling argument FOR it. After all, it's a rather heavy rules "interpretation" we're talking about here.

In short: Somebody just pulled the idea out of a hat. Leave it. Stormcaster is good enough.


EDIT: Just had an idea for an argument, should you still need one: Rogues do sneak attack bonus damage against opponents that are flat-footed, or whom they flank. Would you argue that Rogues do double SA damage if they flank a flat-footed opponent? No? Same principle.