I'm working on the final quest right now... and it is WEIRD. The Heroes discover that the central room's door is locked. They eventually find the Chaos God in an ordinary room. If they search for secret doors in that room, they will find an empty chamber. If that search that one for treasure, they find a key. If they use that key to unlock the central room, they find that it has a throne inside but is otherwise empty... and then the Chaos God's disembodied voice tells the Heroes that they might have won, but that as long as there is darkness in the hearts of men he will return. Or something.
Anyway, half of the quest is post defeating the big main baddie... just to find a room to be told that they won?
I am REALLY tempted to give the Chaos God the Escape spell and have him reappear in that central room for a final battle. I worry that that might be taking too much of a poetic licence, however?
EDIT:
I decided to go ahead with that change. Also, I discovered an issue: Grimdead is not the name of the wizard who resurrected the Chaos God, but the name OF the Chaos God. It looks like the person who translated the earlier quests got a bit confused, so I revised the earlier localizations to reflect that. Also, I changed the wizard's name from Barr to "Borough" because even if the Japanese didn't intend for these two wizards to be the same (and, frankly, I'm not so sure they didn't) it makes much more sense to have them be the same wizard. If they aren't the same wizard, then where the heck is Barr? He resurrects Grimdead and then we never hear from him again? Unlikely. Much more likely that Japanese-to-English translation is as it is... Barr ad Borough are probably one in the same.
