This page of the Resident Evil Village game guide contains a walkthrough on how to get out of Dimitrescu Castle after collecting the 4 masks. Our guide describes how to unlock access to the Tower of Worship, how to defeat the boss Lady Dimitrescu, how to return to the village and more.
Important note - The game won't allow you to return to Castle Dimitrescu later during the campaign. Try to complete all optional activities (exploration, additional puzzles, collectibles, etc.) before solving the mask puzzle and entering the Tower of Worship.
Solving the four mask puzzle
You can proceed to the final stage of Castle Dimitrescu once you find the four masks. Return to the Hall of the Four, which is the location adjacent to the Merchant's Room. You will need to solve the Four Angels' Busts puzzle here with the titular angel busts that have come out of the ground. The location is shown in the attached pictures.
The puzzle itself has a very simple solution, as only one mask will fit each bust. As a result, you can complete the puzzle by trial-and-error, i.e. by trying to place each mask from your inventory on a given statue until you get it right.
Placing the masks may be disrupted by Lady Dimitrescu. If you see (or hear) her approaching, quickly hide in the Merchant's Room, which she cannot enter.
Solving the puzzle will open a large gate and unlock the way to the Tower of Worship. Before you continue, it's a good idea to replenish your health and spend Lei at Duke's shop. You're about to face the biggest boss fight yet.
Boss fight - Lady Dimitrescu
Upon entering the Tower of Worship , try to grab the artifact from the sarcophagus. The main character will be stopped by a large vampire. Lady Dimitrescu will transform into a large flying monster and a full-fledged boss fight will begin. The goal is defeating Lady Dimitrescu once and for all.
When attacking the big monster, always aim for the mutant Lady Dimitrescu "sticking out" of it. It is a small part of the monster's body, so you have to be very precise with your shots. Begin by temporarily chasing the creature away.
Use the stairs and you will find plenty of supplies. Make sure you have collected all the loot. It's also a good idea to make sure Ethan doesn't enter the fight with major injuries.
The first stage of the fight will take place on the balconies surrounding the tower. After the boss appears, always shoot the upper torso of Lady Dimitrescu (optimally with a shotgun or a sniper rifle). Don't go overboard with the number of attacks, though, because the boss may throw herself forward or start charging - in both cases, Ethan may lose a lot of health points.
After each round of shots, retreat quickly, wait for the boss to arrive and then fire at Lady Dimitrescu.
The boss can break through obstacles on the roof - don't treat them as an indestructible shelter. However, it's recommended to look around for optional additional loot along the way.
The boss will rise into the air after receiving enough damage. Keep track of the monster's movements and have your sniper rifle ready. After the boss hovers in the air near the tower, try to shoot at Lady Dimitrescu.
If the attack is successful, the creature will begin to fall and will return to the tower after a moment. If it is unsuccessful, a cloud of flies will be sent towards Ethan. In this case, you can start running away or try to fire at Lady Dimitrescu again to end the "raid" of flies.
The boss will eventually return to the balconies of the tower and you must repeat the steps described earlier - shoot at Lady Dimitrescu and retreat before the monster begins its forward throw/charge. Perform all actions (including successive sniper attacks) until you advance to the second stage of the fight.
You'll advance to the second stage of the fight once the boss performs a powerful charge midair and bursts inside the tower.
It will take a few seconds before you'll regain control of Ethan. Fire at Lady Dimitrescu, while heading steadily up the stairs and avoiding contact with the new clouds of flies. After reaching the very top, it's a good idea to quickly destroy the surrounding vases and collect loot.
The beast will soon burst into the tower through the roof. You must continue to fire at Lady Dimitrescu (again, a shotgun is the best choice here). Try to shoot continuously so that the beast cannot respond with an attack of its own.
As a reward for defeating Lady Dimitrescu, you will unlock the That Sucked! trophy and a very valuable Treasure - the Crystal Dimitrescu worth 25000 Lei.
Returning to the village
Inside the room where the fight took place, you will find a Dirty Flask - the first of four new quest items. More flasks of this type can be found in other locations on the world map.
You'll find the exit from the castle next to it. This path will allow you to explore a completely new part of the village, although you will also return to familiar areas later.