From the climax of Season 6: Axel and Zexion fusing into ANDREW JACKSON, MOTHERFUCKER! And proceeding to lightning-vision the crap out of Belle.
Comic #650 Riku gets put down again... Only to come back, with not only the series' catchphrase, but CAME THROUGH TIME TO DO IT. Badass Emo credentials nearly complete.
And then Emo Mode Riku kills Red XIII. Quoting Optimus. By tearing out his face. Credentials complete.
In Comic #708, Zexion manages to find a (somewhat twisted) response to the The Dark Knight Rises shooting in Colorado: by organizing a fundraiser to train the survivors into "potential Batmen" and fuel a war against injustice.