- Nik Vinter
The ruins of Berez are home to Baba Lysaga. An ancient woman that believes to be Strahd's natural mother. She's a hermit that spends most of the time trying to kill the ravens of the Keepers Of The Feather.
As for the backstory of the town itself: a woman named Marina lived here, she resembled Tatyana and once Strahd met her, he became obsessed by her. He almost turned her into a vampire but before he could do that, the burgomaster managed to kill her, saving her soul. Enraged, Strahd used his powers to flood the village forcing the residents to flee.
The area has the hut of Baba Lysaga, a mansion with the ghost of Ulrich: the ex-burgomaster of Berez, a monument to Marina and an ancient ring of menhirs.
Approaching the Area
The area, similarly to Yester Hill, is very huge and the characters will need a lot of time to search all of the buildings. They will most likely approach from the north, where the road gradually turns into a swamp.
Because of the heavy mist very little of the area will be visible at once.
There are also several scarecrows in the marsh, that appear nonmagical but are actually controlled by Baba Lysaga
Areas Of Berez
Nothing of value is in here, and those are mostly to waste your players' time while they explore them
The ghost of Lazlo Ulrich haunts the mansion. It's a very secondary character and I wouldn't bother running it if he's not your party's ally. To put his soul to rest he has to see Ireea in the flesh, but he can't leave the mansion. He knows the tale of the city but is pretty much useless otherwhise.
Cute little area that has some goats that will act as a lure for inexperienced players. If the players try to free the goats then the skull on the fence will scream as an alarm.
Baba Lysaga's Hut
More on it later.
A monument that Strahd erected in honor of Marina. It's a monument hidden in the marsh and hard to find, Ulrich knows its location. There's nothing interesting here but it adds some depth and flavor to this area's backstory.
A wereraven named Muriel Vinshaw is present here as she's spying on Baba Lysaga. She knows some information about her and will tell it to the players. She also won't tell the players she works for the Wereravens, preferring to leave that as a secret.
In this place there's an ancient ring of menhirs. It's up to your discretion what you wanna do with them, for example you could link them to fanes. A druid entering the circle will feel a connection with ancient gods, and if wildshape is used in here then the druid will get the maximum amount of HP that that form can have.
Baba Lysaga's Hut
Remember that there are ravens (or wereravens if you want) trapped in cages outside so she won't hear anyone approaching (unless one of her alarms had been triggered).
There's a giant scull outside of the hut she will use if a fight starts.
In her hut there's a crib that holds an illusory baby (Strahd), and a bath full of blood she bathes in to prevent aging. There's also a cavity in the floor where the gem that animates the house is (the one stolen from the winery), but the players should't notice it unless the house starts moving.
If Baba Lysaga gets attacked she will command the house to react. The hut will follow her instructions and will fight until destroyed or until the gem is removed, something Lysaga will try to prevent.
Baba Lysaga is the "second mother" of Strahd. She didn't gave birth to him (even though she belives so), but she cast spells on him and placed the spark of magic on him, making him a spellcaster.
Once Queen Ravenovia discovered this morbid attachment to his son she decided to banish Lysaga from the kingdom. She couldn't see Strahd again but followed him everywhere he'd go, witnessing all of his triumphs.
She wished the death of Queen Ravenovia and is desperate because she knows Strahd won't accept her as her mother, so she lives in perpetual denial.
Lysaga hates the wereravens because they try to harm Strahd and put an end to his domain.
If the players confront her she will stay neutral to them, unless she learns that they're here to defeat Strahd or take her gem. She won't try to kill them on the spot but she won't divulge any information with the party either. If the party shows interest in the wereravens, the gems or in Strahd she will become very cautious and will animate the house at the first sign of danger.
If attacked she will use power word: stun on the nearest attacker and will try to get into her flying skull (that gives her three-quarters of cover). She will then try to target ranged casters that are mostly a threat to her, while the hut takes care of the melee fighters. She also has polymorph, so assuming your characters are not properly prepared this will be a really tough fight.
Once the hut is active someone can jump in and take the gem out of the hut. This is a difficult feat as both the hut and Lysaga will try to contrast it.
Special Event: Lost Battlefield
This is another lore-heavy event that happens as your players leave the ruins and could tie them to Argynvostholt. The characters see and hear an illusory battle that happened in the marsh. This is a battle between Argynvostholt's order and Strahd's army.