When players reach Moonrise Towers in Act 2 of Baldur's Gate 3, they can use the opportunity to learn more about the source of Ketheric Thorm's immortality. In fact, Thorm's private quarters hold a lot of useful information about the conspiracy he helps lead.
Unfortunately, most of that information is in Thorm's private quarters on the upper floor of the tower. Not only are all the doors to these rooms locked, the Scrying Eyes and other Absolutist faithful are always watching. Baldur's Gate 3 players can always attack the guards and fight their way through, but there are several more sneaky paths that lead to these forbidden rooms.
Updated October 9th, 2023: Players that want to truly explore all of Moonrise Towers will definitely want to find Ketheric Thorm's room. Not only is this area filled with goodies, but it is adjacent to a special room containing some story-based items that can make it easier to deal with the powerful Oathbreaker Paladin when players eventually face him. To better help players with how to find Ketheric Thorm's room in Baldur's Gate 3, the following guide has been updated to include a video.
How to Enter Balthazar's Chamber
After entering the chapel in Moonrise Towers and speaking to Ketheric Thorm, take the stairs up behind the altar to the third floor of the tower. To the left of the stairs is a large door that leads to the roof, and in front of it is the half-orc Disciple Z'rell. The speaker will need to pass a check to convince Z'rell they're a True Soul (assuming the party didn't side with them in the first act). After that, she'll order the group to help Balthazar get a relic for Thorm.
Even if it's true, players should avoid saying that they met Balthazar. If they don't, Z'rell will assume the party needs a moonlantern and will give them a key to Balthazar's room. Getting this key through conversation makes it much easier to explore this floor of the tower. The door to Balthazar's room is to the right of the staircase on the far side of the library room.
With the key in hand, players can enter Balthazar's room without alerting the guards and without having to pick the lock. Inside is a moonlantern sitting next to the desk at the center of the room. Players can grab it if they don't have one already. The room also contains several valuables and interesting notes, and it has a bookshelf that leads to a secret chamber.
The shelf has four protruding books, and all of them do something. One causes the spikes below the bookshelf to spring up and damage anyone standing too close, one releases a gas that Poisons anyone in the room, and one of them animates the two corpses in the room and causes them to attack the party. The last book (shown in the image below) activates the altar that sits to the right of the shelves.
Once the altar is active, players can place an object on it. Grab one of the hearts in the room (from either corpse or the one on the bloody table) and place it in the altar to open a secret passage. The chest in this secret room holds the Coldbrim Hat and an 
Elixir of Necrotic Resistance
. The book in this room gives players the name "Nightsong," which advances the quest to identify the artifact protecting Thorm's immortality.
The far side of Balthazar's room has a metal door leading to a balcony. Pull the lever next to the door to open it. From here, players have a few options for how they want to enter Ketheric's room.
Entering Ketheric Thorm's Room
Option 1: Pick Open the Door
The most direct route is to open the other door on the balcony behind Balthazar's room. However, the DC to pick open the door is 30, and the metal door is impossible to destroy. A Rogue with expertise in Sleight of Hand can reach this number, but even then, players should expect a few failures before the lock will yield. Fortunately for parties without a Rogue or a ton of 
Thieves' Tools
, there are some easier alternatives.
Option 2: Jump Across
Players may notice the wooden platform next to the door to Ketheric's chamber. This platform is too high for a normal jump, but a character with a triple jump from a class ability, spell, or potion can easily reach it. From there, a party member can go around the side of the tower and make a horizontal jump to a balcony on the other side of the tower. The door from this balcony is unlocked, and it leads to the bedroom of Ketheric's late wife, Melodia.
A locked door connects Ketheric's room and Melodia's, and fortunately the lock on this one is much easier to crack. Party members can also attack it a few times to destroy it and get inside. They can then let the rest of the party in by pulling a lever next to the metal door. An undead guard dog protects Ketheric's room, but players can use a few different skills to convince him to leave the party alone.
Option 3: Climb Up
Even if players never get the key to Balthazar's room, they can still get into Thorm's bedroom without alerting the guards. A ladder or two on the main floor of the tower lead up to the rafters, and on the rafters players can find a set of vines that lead up into Melodia's bedroom. Specifically, players should head to the rafters above the stairs that lead down into the prison. One section of the rafters is isolated, and the vines of this part lead directly into Melodia's chamber.
Players can get plenty of rewards by reaching these rooms. In Melodia's room, the chest at the base of her bed is secretly a mimic, so attack it first to get the jump on it. The mimic contains several gems and a Stained Letter from Melodia to her daughter.
The chest at the base of Ketheric's bed holds a Cloak of Elemental Absorption and a Letter to Ketheric from his wife. Reading these letters will make it much easier to convince Ketheric to stand down during the boss battle at the end of Act 2. Players can also learn more about the plans of Thorm and his allies by finding a book under some loose planks by his bed and by reading other letters and books throughout the room.
Baldur's Gate 3 is available now on macOS and PC. It's coming to PS5 on August 31, 2023.
