Board Thread:Lore Discussion/@comment-5632187-20130119213241/@comment-18016240-20150614015450

The whole deal with Oolacile and New Londo wasn't due to the Dark Soul acting on it's own so much as external forces messing with things using the Dark. In Oolacile's case it was because they were screwing with Manus (who is potentially the Pygmy) and drove him mad, being essentially a Great Lord the same as Gwyn, the Witch, and Nito he had a huge amount of influence over creatures born of the Dark (ie humans) and mutated them due to his rage and madness. The deal with New Londo was likely a failed attempt at ending the Age of Fire/creating a second Lord of Dark on Khathe's behalf, neither case was simply because of humanity's inherent nature, they were both due to outside influences. It seems like the Dark doesn't really have any particular goals or ideals itself, it's just a force of nature like Light, Life (Chaos) and Death.

As for the Hollow form being natural for humans, it's kind of yes and kind of no in my opinion. To me, the original human form is as a shard of the Dark Soul, without humanity you can't really call yourself human. Of course, as Mat said hollowing isn't necessarily a solely human phenomenon. While humans are more likely to go hollow, they're not the only ones who can as seen in Gwyn's case.

In the end, I believe Gwyn deserved to die, both to continue the cycle and because of his actions. What good he did doesn't wash out the bad, and vice versa.