Key takeaways
- The Mason’s Guild occupies the north-eastern section of Reithwin Town, with large stone yards surrounding the main building.
- The area has three practical layers the outer guild grounds, the main guild building and roof, and the Mason’s Guild Basement.
- The basement is central to Investigate the Selûnite Resistance The key evidence is the Mason’s Log, found in the underground Mason’s Hall.
- You can enter the basement through the ornate hatch or the elevator The hidden western passage requires either the Tower-Shaped Key from Mattis or a successful lockpicking attempt.
- The location contains an Infernal Iron, the Helmet of Arcane Acuity, fixed potions and scrolls including a reliable Scroll of Knock, and several pieces of written evidence.
- The main combat encounter is scripted rather than random approaching the meeting table in the basement triggers five Shadows and one Wraith.
About this guide
Spoilers for Act Two, Reithwin Town, the Selûnite resistance and several companion quests.
Overview
The Mason’s Guild is a substantial location in the north-eastern part of Reithwin Town during Act Two of Baldur’s Gate 3. It is not merely the guildhall building. The location includes the guild’s outer yards, work areas, roof, cellar access and a hidden basement containing the remains of a Selûnite resistance meeting place.
The guild is one of the most useful places to investigate if you are following Investigate the Selûnite Resistance, looking for Infernal Iron for Karlach, or collecting Act Two equipment. It is also an atmospheric link between Reithwin’s former civic life, Ketheric Thorm’s suppression of Selûnite worship and the surviving evidence of the town’s underground opposition.
Overview and boundaries
The Mason’s Guild is a location within Reithwin Town, not a separate region and not a synonym for the whole north-eastern district. Its boundaries include the guild’s building and the extensive yards around it. The building stands among abandoned masonry projects, stone blocks, unfinished statues and plaques. The rear of the property opens towards a side stream of the River Chionthar, with the protected dome of Last Light Inn visible across the water.
The guild should be kept distinct from the neighbouring locations:
The guild was once a functioning centre of civic construction. By the time the party arrives, it has been abandoned under the Shadow Curse. Its stonework and unfinished projects suggest that normal work stopped abruptly rather than being carefully closed down. The basement, however, shows that the guild later became connected to the Selûnite resistance against Ketheric Thorm and the Sharrans.
Named directory: location and subareas
The last group contains neighbouring or connected places, not internal subareas of the guild.
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Named directory: location and subareas
Getting there
From the Ruined Battlefield
The most direct external route begins at the lesser stone bridge from the Ruined Battlefield, at approximately X: -59, Y: -22. This bridge has a damaged archway and a wooden section. Crossing it leads towards the eastern gate of Reithwin Town and then the guild grounds.
This route is useful if you have entered the Shadow-Cursed Lands from the western approach and want to reach the Mason’s Guild before exploring the rest of Reithwin.
From Reithwin Town
Two gates connect the guild grounds to Reithwin’s streets and central area. If you have already activated or reached the Reithwin Town Waypoint, walk north or north-east towards the large masonry complex.
The building is difficult to mistake. The yards contain blocks of stone, half-finished statues and extensive work areas, making the guild visually distinct from the surrounding residential and religious buildings.
From Reithwin Graveyard
The guild can also be reached by climbing or following the thick vines leading from parts of Reithwin Graveyard. This is a useful route if you are already exploring the graveyard, searching for the Grand Mausoleum, or following activities involving Arabella and the Thorm family tombs.
Shadow Curse preparation
Reithwin Town is more deeply affected by the Shadow Curse than the Ruined Battlefield. Ordinary light and the basic Blessing of Selûne are not sufficient protection in the town. Bring a functioning Moonlantern or obtain Dolly Thrice’s Pixie Blessing before travelling through the area.
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Guild yards and exterior works
The outer grounds are spread around the main building. They contain abandoned stone blocks, unfinished statuary and plaques. There is no functioning mason, merchant or guild official to speak with, and no shop operates here.
The yards are nevertheless worth searching carefully. The most important exterior pickup is an Infernal Iron in the backyard, approximately at X: -102, Y: 18. If Dammon survived Act One, this can be taken to him for Karlach-related progression or to produce a piece of rare armour.
The exterior also provides access to the building’s side balcony, roof and cellar elevator.
Exterior directory
The impaled skeletons are environmental storytelling rather than a named NPC encounter. Their warning suggests that people who resisted Shar were publicly punished. The evidence supports the interpretation that the Mason’s Guild leadership was destroyed after the Selûnite resistance was exposed, although the exact circumstances surrounding Morfred’s death are not stated with complete certainty.
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Main guild building
The main building is abandoned but largely intact. It contains the guildhall, the remains identified as those of the Grand Mason, a rear workroom, access to the roof and the descent into the cellar.
Korrilla’s appearance
When the party first approaches the guild, Korrilla may be seen near the central gates, spying on the party at approximately X: -110, Y: -20. She normally teleports away before she can be properly confronted. A fast character may trigger a short exchange, but this does not produce a substantial quest or reward. If she escapes, companions may comment on the sulphur smell left behind.
Korrilla’s presence is a reminder that the guild is being watched by forces connected to Raphael and the wider Act Two plot, even though she is not a permanent resident of the location.
Grand Mason’s remains
Inside the main building, a Perception check can reveal a pile of “odd looking bones” on a marble plinth. The plaque identifies them as the remains of the Grand Mason.
Inspecting the remains and reading the plaque can grant:
This is primarily a lore and inspiration interaction. It does not initiate a major combat encounter.
Rear workroom
In the far room of the building, approximately at X: -117, Y: 31, a workbench contains:
These are fixed pickups rather than merchant stock. The workroom is also a useful place to search if you are short of lockpicking or trap-disarming supplies before entering the basement.
Building directory
The Barkskin Recipe lies inside the main building at approximately X: -110, Y: 3. It is a piece of written alchemical material and should be collected before leaving if you are maintaining a thorough book and recipe collection.
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Building directory
Roof and upper access
The roof is reachable through the building’s upper routes and may be searched separately from the interior.
A heavy chest on the roof, approximately at X: -113, Y: 0, contains gold. Two skeletons at around X: -115, Y: 22 also provide loot:
These are ordinary remains rather than active undead enemies. The roof does not contain a named boss or a separate quest stage.
Roof directory
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Cellar and entrance to the basement
The hatch is approximately at X: -127, Y: 26–27. The elevator provides a second route and is useful if the hatch is difficult to locate or if you are exploring the building from the balcony.
The cellar itself is not the main quest chamber. The significant area lies behind a concealed wall accessed through the Keyholed Herald.
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There are two practical ways to descend
- 01Use the Ornate Wooden Hatch in the rear part of the building.
- 02Use the Control Wheel on the side balcony to operate the elevator.
Mason’s Guild Basement
The basement is the most important part of the location. It contains the hidden remains of the Selûnite resistance’s activity and the combat encounter associated with the guild’s underground meeting area.
Unlocking the hidden passage
In the basement, a Perception check with a listed difficulty of DC 10 reveals the Keyholed Herald on the western wall. The concealed mechanism can be opened in either of two ways:
The Tower-Shaped Key can be obtained from Mattis at Last Light Inn. He may sell it for 1,000 gold, or the party can obtain it through dialogue checks. If Mattis is unavailable, the key may instead be found in a cobweb-covered pouch behind the inn’s main bar.
Opening the Keyholed Herald reveals a movable wall and a secret passage. A threatening Note from the Mason is pinned inside.
The trapped reinforced chest
A reinforced gilded chest lies in the passage area at approximately X: 104, Y: -700. It is deliberately awkward:
The gargoyles fire Fire Bolt. The chest is therefore a trap encounter rather than a simple locked container. If your party is not prepared to disarm it, consider leaving it alone or positioning the rest of the party before attempting the interaction.
Mason’s Hall and the ambush
Beyond the trapped section is the Mason’s Hall, a large underground chamber with a lowered central floor and galleries on both sides. A long stone table stands at the far end. This appears to have been the Selûnite resistance’s meeting place.
The trigger occurs roughly halfway through the room, whether the party uses the central floor or the galleries. This is not a random encounter and does not depend on resting or party composition.
Combat advice
The encounter is dangerous because Shadows can drain Strength and exploit darkness. Useful precautions include:
Evidence on the table
Reading the Mason’s Log completes the Mason’s Guild stage of Investigate the Selûnite Resistance. The text explains that the mason made an arrangement with Raphael, described as “the man who was no man”, in an attempt to eliminate Ketheric’s Dark Justiciars in their stronghold.
The Mason’s Letter and Mason’s Log are story-critical evidence for this location. Take care with area-of-effect spells before reading them. A spell effect that damages the table or the book can destroy the Mason’s Log and make the intended completion step unavailable through that copy. The quest may still be advanced through other evidence in some states, but the safest approach is to read the book before using fire or destructive area effects in the room.
Helmet of Arcane Acuity
Behind the altar is another trapped gilded chest. Its requirements are:
The trap uses Guiding Bolt rather than a conventional mechanical effect. The chest contains the Helmet of Arcane Acuity, a notable Act Two item for builds that want to improve spell save DC or weapon attack accuracy after hitting with weapon attacks.
Eastern gallery stash
A Perception check of DC 10 on the eastern gallery reveals a button at approximately X: 123, Y: -739. The button opens a concealed door to two heavy chests.
The scroll and potion selection is fixed rather than a general random-container table, making this one of the more reliable places to obtain a Scroll of Knock.
A Moonrise Diagram sits on a nearby table. Taking or reading it adds a secret stash to the map of Moonrise Towers. Bookcases along the galleries mostly contain common books, although the bookcase beside the Moonrise Diagram contains a random rare or uncommon spell scroll.
Basement directory
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Eastern gallery stash: The fixed contents include
| Container | Contents |
|---|---|
| Potion chest | Potion of Invisibility, Potion of Speed, Potion of Glorious Vaulting, Elixir of Darkvision |
| Scroll chest | Several scrolls, including Scroll of Knock |
Investigate the Selûnite Resistance
The Mason’s Guild is the final major investigation site for this quest. The quest can begin through evidence found elsewhere, including Investigation Notes on the skeleton of Inquisitor Verzen Wranlock or a note in the Potter’s Chest in the Ruined Battlefield.
The quest reveals that the Mason’s Guild was connected to the Selûnite resistance and that its leader, Morfred, was determined to continue opposing the Sharrans. The game strongly suggests that the guild’s leadership was punished after the resistance was uncovered, although the precise account of Morfred’s execution is reconstructed from circumstantial evidence and environmental clues rather than a single definitive scene.
The broader route is
- 01Find the evidence concerning the Sharrans’ investigation of the former Selûnite hideout.
- 02Investigate the Potter’s Chest in the Ruined Battlefield.
- 03Follow the evidence to Last Light Inn.
- 04Search the Last Light cellar and locate Halfred’s Note.
- 05Obtain or bypass the Tower-Shaped Key from Mattis.
- 06Enter the Mason’s Guild basement.
- 07Open the Keyholed Herald.
- 08Defeat the Shadows and Wraith in Mason’s Hall.
- 09Read the Mason’s Log.
Forging a Heart and The Hellion’s Heart
The guild contains Infernal Iron, which is relevant to Karlach’s personal storyline and Dammon’s work. This is not a separate Mason’s Guild quest, but the item makes the location important for parties travelling with Karlach or progressing The Hellion’s Heart.
If Dammon survived Act One and remains available, bring the Infernal Iron to him. He can use Infernal Iron to make rare armour, and the process may advance Karlach’s quest. Dammon’s presence and availability depend on earlier progression states, so the guild’s item is fixed but its ultimate use is not guaranteed in every playthrough.
Quest directory
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Named characters associated with the location
There are no permanent living residents or functioning guild staff in the Mason’s Guild when the party explores it.
Korrilla
Korrilla is a visitor and observer rather than a resident. She may appear near the entrance, then teleport away. This encounter is brief and has no substantial local reward.
Morfred
Morfred is not present alive. He was the apparent leader of the Selûnite resistance and the former head of the guild. His writings and the guild’s evidence establish his importance to the location’s history.
Mattis
Mattis is not in the Mason’s Guild. He is a trader at Last Light Inn and is included here because he can provide the Tower-Shaped Key required to open the hidden basement route. The key may be bought, obtained through dialogue checks or recovered from the inn if Mattis is absent.
Dammon
Dammon is not a guild resident. He is relevant because the Infernal Iron found in the guild can be taken to him if he survived the events of Act One.
Faction directory
The guild itself is not controlled by an active faction during exploration. The Selûnite resistance is represented through documents and remains, while the Sharran aftermath is represented by the punishment outside the guild and the undead in the basement.
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Loot and collectibles
Other loot
The potions and scrolls in the hidden gallery storage are fixed. The gallery bookcase spell scroll is random within the stated rarity range, so it should not be treated as a guaranteed specific spell.
Collectible and evidence checklist
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Recommended exploration route
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For a thorough but efficient visit
- 01Enter the guild from Reithwin Town or the Ruined Battlefield bridge.
- 02Search the yards, including the backyard Infernal Iron.
- 03Enter the main building and collect the Barkskin Recipe.
- 04Inspect the Grand Mason’s bones and plaque.
- 05Search the rear room for thieves’ tools, a trap kit and the Burning Hands scroll.
- 06Reach the roof and search the heavy chest and skeletons.
- 07Return to the side balcony or rear room and descend by elevator or ornate hatch.
- 08Make a Perception check in the basement for the Keyholed Herald.
- 09Open it with the Tower-Shaped Key or lockpick it.
- 10Read the Note from the Mason.
- 11Prepare the party before approaching the long table.
- 12Defeat the five Shadows and Wraith.
- 13Read the Mason’s Letter and Mason’s Log.
- 14Search behind the altar for the Helmet of Arcane Acuity.
- 15Find the eastern-gallery button.
- 16Loot the fixed potion and scroll chests.
- 17Take the Moonrise Diagram and inspect the bookcases.
- 18Return to Dammon with the Infernal Iron if Karlach’s quest requires it.
Hazards and missable content
Shadow Curse protection
Entering Reithwin without adequate protection can damage or kill characters over time. This is an area-wide progression hazard rather than a Mason’s Guild-specific trap. Bring a Moonlantern or Pixie Blessing before making a long exploration route through the town.
Destructive spells and the Mason’s Log
Avoid fire and uncontrolled area damage around the Mason’s Hall table until you have read the Mason’s Log. The book can be destroyed, which may prevent the normal completion step for the investigation.
Keyholed Herald
The Tower-Shaped Key is convenient but not mandatory. A character with the necessary Sleight of Hand can open the mechanism directly. Conversely, obtaining the key from Mattis is progression-sensitive. If Mattis is no longer available, search behind the bar at Last Light Inn before assuming the basement is inaccessible.
Infernal Iron
The Infernal Iron is a fixed item, but its importance depends on Dammon’s survival and current location. If Karlach’s storyline matters to your party, collect it before leaving the guild and check whether Dammon is still available.
Trapped chests
The reinforced chest near the secret passage and the chest behind the altar are separate traps. The first can isolate the interacting character and release gargoyle statues. The second fires Guiding Bolt and has a high disarm difficulty. Make a manual save before attempting either chest.
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Lore
The guild is one of Reithwin’s clearest examples of a civic institution turned into a historical crime scene.
Before the Shadow Curse, Reithwin was a prosperous settlement on the Risen Road near the River Chionthar. Its wealth and civic identity were expressed through stone streets, elaborate construction and large public works. Morfred, the local mason, was commissioned by Ketheric Thorm to build a grand Selûnite bastion at Moonrise Towers.
Ketheric’s conversion from Selûne to Shar transformed the political and religious climate. Selûnite worship was suppressed, and the town became associated with the Sharran army and the Dark Justiciars. The Mason’s Guild appears to have become one of the remaining centres of organised resistance.
The unfinished stonework and abandoned yards suggest the Shadow Curse interrupted ordinary work. The basement documents show the later resistance network, while the impaled skeletons outside demonstrate what happened to those who opposed Shar. The location therefore links three different stages of Reithwin’s history:
The pact or arrangement involving Morfred, Raphael and the Dark Justiciars also connects the guild’s local history to the broader supernatural politics of Act Two.
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Lore: steps
- 01Prosperous civic construction.
- 02Ketheric’s religious and political oppression.
- 03The collapse of the resistance under the Shadow Curse.
Sources
- Mason's Guild - bg3.wiki — bg3.wiki
- Reithwin Town - bg3.wiki — bg3.wiki
- Investigate the Selûnite Resistance - bg3.wiki — bg3.wiki