Does this mean your
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quanta must match the creatures HP exactly? Or will it be able to kill anything with less HP than you have
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in your pool?
I'm guessing you mean the latter, since the former would probably be situational and UP.
Its definitely a bit more powerful than a standard bolt for taking down large creatures, so I think it will fit a slightly niche than bolts.
Considering the level of stored quanta needed scales with the targets HP, I think this should be enough to justify a one-shot kill kind of effect...
Of course, you are likely to get people complaining about adding to fire's already abundant CC supply...