It's crazy how strong it is, continual hits stack with each other reducing the armor rating further into the negatives, combined with the short cool down its brilliant against durable enemies with lots of health but not much armor rating (basically every enemy in skyrim, the most armor rating you will find is 100).
It seems it's better to continually use the first level of the shout than the second or third, the extra cool down isn't worth the extra effect.



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