Is it actually meant to be 3000 damage instead of 30000? I can understand 666 being a special number for another achievement and will willingly grind for it, but is 30000 a significant number that happened in whatever fun trivia (LOTR?) behind this? The Orc Shaman achievement 5000 damage was completed almost within one run for me.
(I understand the achievements are easier in terms of concept, compared to earlier titles)