As part of the main story in NieR Replicant 1.22, you’ll be asked by Yonah to check on her friend.
Her pen-pal apparently lives in a manor just south of the village.
Here’s a walkthrough on the Haunted Manor in NieR Replicant.
When you first enter the manor, the butler will ask you to wait at the dining table. Kaine will just sleep on the sofa instead.
If you explore the area and then come back to the dining hall, you’ll realize that Kaine is missing.
Look for the first key
Explore the manor and look for this open space (with a fountain) in the image below. You’ll see some people who have been turned to stone.
Go to the door on the left.
Inside the room, take the key and go back through the fountain area.
Once you get back, you’ll notice some Shades. Take them out first.
Then, head to the door on the uppermost corner and use the key.
Get the Star Key
In the next area, turn right towards a corridor that has a single spider. Defeat the spider and enter the room.
You’ll find the small boy who is the owner of the manor.
Emil will give you a map to the manor and a Star Key.
Examine the rooms for the Light Key
After coming out of the boy’s room, continue to the unexplored part of the manor.
You’ll find a corridor with many rooms near each other.
Some rooms will have Shades while others are just weird.
In one of the rooms, you’ll get the Light Key.
In another room, you’ll find the butler inside. Talk to him.
The boy Emil will also join you guys.
You should get the Darkness Key.
Head to the boss room
The aim now is to find a cure for the boy Emil which is in the big room in the middle. It’s also the boss room.
Along the way, more Shades will spawn. This time, Emil will help you in battle as he can turn them to stone.
You’ll have to use the Darkness Key for one of the locked doors.
In the next area, you will find a one-handed sword known as the Blade of Treachery.
Before you enter the boss room, remember to save the game using the post box.
Defeat the boss
Inside the room, you’ll find a black book.
To damage the book, you need to use melee. Just watch out for the spinning book-blade from time to time.
Towards the end of the fight, the book will have a barrier around it. It can also charge towards you but you can dodge it.
You can use magic to attack the barrier but it’s pretty slow. The best time to damage it is when the barrier goes down a few seconds.
After the fight, you would have collected all the Sealed Verses. This one unlocks the Dark Whirlwind magic.