Not sure if you got my message or not, but I have hard mode aetheon saved on my titan if you are just wanting to kill him. He is the one who drops the helmet, vex mythoclast, and timebreaker. If you are wanting to run through the whole thing, i haven't done it on my warlock yet. But anyone wanting to save the aetheon fight on hard to their character, let me know and i will get you in. Just send me a message or add me as friend. Phoenix_Flame234