Unfortunately, I think you might be stuck outside of finding an item editor somewhere that will let you spawn in the Ashen Mist Heart. Seems the Ancient Dragon is not assigned his droppable loot until he's been designated as an enemy by the game (which doesn't happen until you attack him). That might seem to be an oversight as most others who can be attacked in the game still drop their loot even if they were killed before being made "hostile." I guess From figured that nobody, regardless of builds and buffs, was going to be able to deliver over 19,840 damage in a single non-backstab, non-plunging attack!
Semi-similar thing happened to me when I went through the game the first time using this cheat - I walked up to the Ancient Dragon and talked to him, got the Ashen Mist Heart as a result (so at least I could continue the game), then attacked him with "Easy Kills" turned on and when he died he did not drop his usual items (Giant Soul, Petrified Dragon Bone).
Solution I think will work would be to talk to him first to make sure you get the Heart, deactivate Easy Kills and attack him until you see his health bar, indicating the game has repurposed him as an enemy, then reactivate Easy Kills and take him out.
In your case, the only non-item editor way I can think of to continue is to use a Bonfire Ascetic on the bonfire at the Dragon Shrine entrance to respawn the Ancient Dragon. Don't know if he'll still be hostile if you do that (run up to his location and if there's a fog gate, he's hostile - if not, he's not), so if you want to try my above method of talking to get the Heart (the only necessary item to continue) and then attacking, you might first want to warp over to Brightstone Cove Tseldora and talk to Cromwell to "pardon your Sin," which will de-aggro him.
I haven't actually tried this though so I have no idea if it will work.
Important Board Topics
Trending Topics