Er, it's phrased kind of awkwardly. I believe Odium is referring to this scene from KHIIFM, where we learn from Zexion and Xigbar's conversation that...
I sort of figured it was Luxord as well. Since he spent some time in Port Royal with all the treasure in the Isla de Muerta, it seemed to make sense...
Always, always wait until after the credits. It's becoming very common to keep important scenes for after, to encourage the audience to actually stay...