Oh man, we lost a lot here. Not even sure where to start, but let's talk about enhancing Castle Ravenloft because that's where my group is now- and we're playing tonight! 6th level, with the Sunsword and Holy Symbol of Ravenkind. They went down instead of up and met Cyrus, who they tied up.
What advice and pro-tips do you all have for the Castle.
I've kept a digital timer going to remind me to roll for wandering monsters every ten minutes outside of an encounter. Keeps the pressure on.
Hrm... they have the Holy Symbol and the Sunsword but are only 6th level? Yeesh. They might very well be in trouble. Yes, they have the two items necessary to allow for a permanent destruction of Strahd (the two items that can generate true sunlight).. but aren't nearly the level necessary to stand up to a hit 'n run assault by the Vampire Lord should be decide to put them down once and for all.
Thus if I was in your shoes... I think that if the party is now going through the castle making a nuisance of themselves (especially since they're tying up the castle's manservant), I'd make it a point to have Strahd not take that sort of affront lying down, but also not willing to get his hands dirty. The next time the party does something actually against the castle or one of its inhabitants... I'd probably have Strahd send a good half-dozen Vampire Spawn after the party to put them in their place. The book says that any previous adventurers to Barovia who attempted to go after him were made into Spawn, and there are always many places where Spawn show up across the valley... so having a large supply of Spawn available on hand, and him send an adventuring party of Spawn (or two) after your group is not out of place.
At that point... if your group puts the Spawn down, then Strahd realizes who he is up against and will start getting pissed (and thus devious). But if the group gets taken out by the Spawn because they just aren't high enough level to accomplish it (and/or because they haven't yet found the Tome of Strahd, and thus not learned whatever other "weaknesses" the book might state he has)... then some can be allowed to flee, while others might get knocked out and then later wake up to find themselves either bitten, or at the very least locked within one of the crypts underneath the castle.
I can't remember which of the various Ravenloft books/adventures this info has been printed in (or indeed if I just cobbled all of it together from various sources into one infodump)... but I might take the history of Saint Markovia as a good indicator of what might happen if the party is becoming too much of a threat:
SAINT MARKOVIA
Lore: As a youth in the village of Kresk, the young woman Markovia followed her heart and became a priestess in the church of the Morninglord soon after her eighteenth birthday. She proved a charismatic proselytizer and a cunning warrior, and consequently rose quickly in reputation. By her late twenties she had become a paladin, and had gained a reputation that no evil could stand before her. One day, the vampire Strahd heard townspeople make the boasts that Markovia could probably defeat even the Master of the Castle himself, she was so holy. Enraged by this comparison and the besmirchment of his power, he sent a passel of vampire spawn to her small home in Kresk that very midnight. They confronted Markovia in her sanctum and were destroyed to a one. Suffused with righteous victory after defeating a force of vampire spawn, Markovia advanced on Castle Ravenloft that very night. A great battle raged from the highest catacomb to the lowest parapet, but in the end, Markovia never returned to Kresk, and the Master of the Castle long walked with a limp and a grimace of pain. It is said he trapped Markovia in a crypt beneath his castle, and her remains linger there yet.
There is still plenty of time for you to keep the adventure going. It need not be a "Fight for the final time!" situation right now. They may want to try and go for the endgame at this point, but you have a lot of things at your disposal in the castle before sending Strahd in on a "All or nothing!" attack. Play with your players a bit... don't let them take it easy in the castle... especially if they act like they own the place have Strahd show them who the real Lord of the castle is.
Then, once they've left, gotten more powerful, found the Tome, and found their ally... then they can come back for the final showdown.
