BG3 Necromancy of Thay guide

Across the vast and intricate world of Baldur's Gate 3, some secrets you find early on in your adventure aren’t fully revealed until it’s almost at its end. In a Necromancer’s cellar in the Blighted Village, you find the eldritch Necromancy of Thay, an evil book filled with the kind of knowledge it’s best not to know.

But, if you do want to conquer the powerful magic the Necromancy of Thay has to offer, here’s everything you need to know.

How to destroy the Necromancy of Thay

If you think evil magic is best destroyed, then it is possible to burn the book without reading it. First, place the Necromancy of Thay on the ground, then hit it with a spell or weapon that deals Radiant damage.

The easiest way to do this is with Shadowheart’s Guiding Bolt.

When you do, three evil shadows will pop out and attack you, but defeat them and the book will be truly vanquished.

How to read the Necromancy of Thay

Pick up the Necromancy of Thay and either take it for yourself or let one of your companions have it. Astarion wants the book, and you can give it to him for a relationship boost.

To open and read the Necromancy of Thay, you first need to find the Dark Amethyst in the Whispering Depths. To find the Whispering Depths, go to the Blighted Village and climb down the well in the middle of the village.

Next, make your way through the Whispering Depths, past the difficult Ettercap monstrosities, to the Phase Spider Matriarch - a giant spider boss.

You can either take her on nobally, first attacking her, then the swarms of tiny spiders she spawns, or you can be a bit naughtier.

Sneak up to the Matriarch and you have two choices. First, if you still want a bit of a challenge, attack the web bridge underneath the spider’s feet. This will cause it to fall down to a lower level for some hefty damage.

Alternatively, if you’re travelling with Wyll - or are a Warlock yourself - and have upgraded Eldritch Blast to include a knockback effect, simply target the unsuspecting Phase Spider Matriarch while it’s close to the endless chasm and you can push it off to an instant demise.

With that, climb down the nearby web to underneath where the Matriarch was patrolling and you can snag the Dark Amethyst.

Now, slot the Dark Amethyst into the front of the Necromancy of Thay. You need to pass three saving throws to read the book to completion. But this will allow that character to cast the Speak to Dead skill, which is very useful throughout your quest for solving murders, finding lost items and generally gathering information from dearly departed characters.

However, while you can’t access them yet, there’s still yet more to learn from the Necromancy of Thay.

How to unlock the Necromancy of Thay

To access the rest of the Necromancy of Thay, you need to access Sorcerous Sundries vault and find the Tharchiate Codex. This isn’t accessible until Act 3 of Baldur’s Gate 3, when you reach the Lower City area of Baldur’s Gate.

Once you do though, you find the Tharchiate Code in the Elminster section of the Vault on the eastern side of the area.

To unlock the Elminster vault, go through the Silverhand door, then the Evocation door, then open the Wish door.

Inside there’s another lever which opens the Elminster vault.

Then go through the gate to get back to the previous room, then walk through the Illusion door.

This gets you back to the start of the puzzle with the Elminster vault open.

Inside you find the Pyroquickness hat, some scrolls, potions and gold. Break, pick or cast Knock on the display case and you can claim the Tharchiate Codex.

Read the Tharchiate Codex with the character you want to open the book and you learn the secret to unlocking the Necromancy of Thay, but receive a curse lowering your Constitution.

Next, read the Necromancy of Thay. Pass the saving throw and you take the knowledge for yourself, granting that character the unique ability to summon undead ghouls to fight alongside you with the Danse Macabre skill.

You can then remove the curse with the Remove Curse skill, or a scroll (there’s one conveniently on sale downstairs in Sorcerous Sundries at the bookseller, Tolna).