You need to KWTD! Must have at least 100 completions, have a kd of no less than 327.0, and have Gjallerhorn equipped in all three slots. Furthermore, you should also be able to solo all raids with the beginning weapons and armor. I think that's it.
I have 10 completions solo already. Got the emblem to prove it but Unfortunatly i deleted it by misstake :)