Wait people, remember that C'thun supposedly fought with a Titan and barely managed to survive (the Titan did not).

What if our friendly neighborhood Titan did serious damage to the Old God? What if we're fighting this guy at his absolute weakest (much like Ragnaros)?

My guess is that C'thun has not recovered from his clash with the World Shapers, and has been using the Silithid and Qiraji as puppet armies to keep the world from knowing this. When we reach him, we may see that he's at 10% of his true strength. But this was all a theory, and nothing more.

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Rationalizing the irrational since 2005.