There should be epic battle achievements. level 1 = completed the EB level 2 = unlocked the EB in a clan level 3 = unlocked the EB first among all KAW (you were active in the first clan to defeat it in on their unlock) Level 3 would give pride to the unlockers who, without help from guides, open a new EB first, and level 2 would encourage people to help other clans access new content. You could add rewards, like +1% drop rate for equip-able items from that EB.
If level 3 is what I understand, you cannot get that achievement already as the first clan has actually done it. And so you miss out on Calydor, Z'uthmerak, Thorak, and many more.