How to Beat Thisobald Thorm BG3 – Baldur’s Gate 3

Today we are going to take a look at how to beat Thisobald Thorm in BG3. Thisobald Thorm is an optional boss fight found in Act 2 of Baldur’s Gate 3. It’s quite a tough fight that is mechanically heavy, and the boss can deal high damage to multiple allies at once.

In this guide, we will help you with what you need to do to defeat Thisobald Thorm. It obviously contains some spoilers about the boss and the fight, so if you haven’t reached it yet and don’t want to be spoiled, then it’s best not to read on for now.

Thisobald Thorm BG3 Boss Guide

There are two ways of dealing with Thisobald Thorm in Baldur’s Gate 3. It’s possible to avoid the fight entirely by agreeing to drink with him and succeeding multiple persuasion checks to get him to keep drinking.

If you fail the checks or decide not to use that method, then you’ll need to fight him instead.

Party Positioning

To have the best chance in the Thisobald Thorm boss fight, it’s recommended to have good party positioning. Ungroup your characters before beginning so you can position each one manually and have them stay put. We found that it’s best to spread everyone out. The tankiest person should stand downstairs near the boxes, with everyone else above them on the ramp for the high ground bonus ( but spread them out a little). In our case we positioned the Cleric downstairs and the Ranger, Wizard and Druid upstairs. The boss normally attacks the closest target to begin with, so this way they’ll hopefully start by attacking your tanky character, buying the rest of your party some time. If you have any summons, you can put them near the boss so it attacks them first. This is generally always a good trick in Baldur’s Gate 3.

Thisobald ThormBG3 Boss mechanics

Thisobald Thorm has a few mechanics that you need to know about in BG3. They all focus on Thisobald’s vice – drinking.

1. Thisobald starts the fight with immunity to all piercing, slashing and bludgeoning damage, meaning magic is your only way to damage him.
2. Dealing any magic damage types to Thisobald will add that damage type to his brew. Adding multiple elements turns it into a necrotic brew.
3. If the boss has a brew ready on his turn, he will regurgitate it. This is a small AOE that can deal around 30-40 damage on normal difficulty, which is why everyone should be spread out. Throw every type of damage mitigation, saves and avoid death effects that you have on the person tanking the boss, so they have a chance to survive it too, and try to heal them up after.
4. Each time the boss does the brew attack, it gains a stack of delirium. While delirious, he may spawn imps in the fight, which give 50% resistance of a particular element to everyone standing near them. When this happens, if possible attack the boss with whatever element the imp gives resistance to, to give you a better chance of surviving his next brew.
5. After doing 3 brews, his delirium gets so bad that he blacks out for 1 turn, losing his resistances and giving all your attacks against him advantage. Hit him with absolutely everything you have in this stage.
6. After waking up, he’ll spend another turn recovering. At this stage you lose your advantage against him, but he can still only do his basic attacks.
7. After recovering, the cycle begins again. Ideally you should be able to kill him before reaching this point. It’s very hard to survive the brew phase twice.

Thisobald Thorm Boss Fight Strategy

Now to some info about the strategy we used to beat the Thisobald Thorm boss in Baldur’s Gate 3. Since there are also a few adds with the boss, it’s a good idea to put some effort into getting rid of them. This is best done during the brew phase, with characters who can’t deal much (or any) magical damage.

We recommend doing a Long Rest just before the fight, to ensure that everyone is full HP and you have all of your Spell Slots available. You need to drop a lot of damage on the boss quite quickly, so don’t hold back with spending your second and third level spells.

During the brew phase, just keep chipping away at the boss’ health as best as you can. After an imp spawns, try to use the same type as magic on the boss so you can resist his next brew. For example if he spawns an Ice Imp, then use Ice/Cold Magic to damage him more.

It might take a couple of attempts to reach the blackout phase of the fight with everyone still alive – but this is quite important to dealing high enough damage to the boss during the blackout phase, so that you’re able to nuke him before he recovers.

Thisobald Thorm Tips

Use the Heat Metal spell to make the boss drop his weapon. If it succeeds you can pick the weapon up and put it in your inventory by right-clicking. This will reduce his damage output from melee attacks, but he’ll still be able to do his regurgitate attacks.

Use any summons from your Cleric, Wizard, Druid or any other summoner you have such as familiars and spectral weapons to keep the boss or the adds busy.

The adds aren’t hugely dangerous individually but can cause real problems if you allow them to gang up on one party member. Astarion’s Rogue Build is good at taking them out.

The imp also attacks you but only has 4HP. It’s still recommended to leave it alive so you can get resistance to the brew attack from the boss, but if you want to be greedy with the damage and risk taking the Necrotic Brew then you might as well kill the imp so it doesn’t deal damage to you. You can do the fight this way, the boss will just hit harder.

We hope this Thisobald Thorm BG3 boss guide helped you defeat the very tough boss in Baldur’s Gate 3.