Baldur’s Gate 3 – How To Beat Ketheric Thorm

There are many bosses that you have to eliminate in Baldur’s Gate 3. Ketheric Thorm is one of them, and he lords over the Shadow-Cursed Lands in Act 2. As a necromancer, he’s also impossible to kill, thanks to his mastery over death. Our guide discusses how you can beat the Baldur’s Gate 3 Ketheric Thorm boss, as well as details for each encounter. Likewise, please be reminded that this guide contains spoilers.

How to Beat Ketheric Thorm in Baldur’s Gate 3

The Baldur’s Gate 3 Ketheric Thorm boss fight concludes the game’s second act. Before you can get to that point, however, you need to do a plethora of tasks:

Jaheira’s Recruitment

Assuming you ensured that Jaheira remained safe, you should be able to recruit her soon enough. Here’s the gist:

• The Harpers will assault Moonrise Towers. Jaheira wants to lead her own force, but you must convince her to join your party. This turns her into a follower that you can control manually, as opposed to an AI unit that could be very reckless.
• After clearing the first phase of the Ketheric Thorm boss fight (more on this shortly), you can tell Jaheira to join your squad. This makes her a full-fledged companion. However, you won’t be able to dismiss or replace her until you’ve totally put an end to Thorm. She simply won’t have that dialogue option while Thorm is still undead and kicking.

The Fight Against the Cult of the Absolute

This battle takes place in the large area leading to the interior of the tower. You’ll face over two dozen cultists here, though you’ve also got many Harpers as backup. Here’s what you need to know:

• Disciple Z’rell is the most dangerous combatant here due to her Black Hole spell that funnels multiple units, while slowing them down. This is usually followed up by AoE spells from other enemy casters.
• There are several archers on the wooden beams, though they should still be easy enough to hit.
• Ideally, you should cast AoE spells like Ice Storm, Fireball, and Guardian of Faith on the wide-open area. This ensures that multiple hostiles get hit as they move closer to your army.
• Your rewards include several rare and very rare items. Opponents here also drop Soul Coins and Mind Flayer Parasite Specimens. Be sure to loot the dead like a grave robber extraordinaire.

Ketheric Thorm Phase 1

Upon reaching the top of the tower, you’ll start the first phase of the Baldur’s Gate 3 Ketheric Thorm boss fight. Here’s the gist:

• Thorm is flanked by a skeleton dog, another cultist, and several Necrolites. Most aren’t that threatening, but he does cast Incubate Death. It spawns a Necrolite on the next turn, so be ready to take a few hits.
• Thorm also bashes anyone who hits him in melee, which can potentially knock down a character.
• If you saved the Nightsong, then she’ll assist you during the fight. She hits extremely hard, though she’s not immune to knockdowns.

Once you bring Thorm down to 40% HP, a cutscene will trigger. A giant tentacle will appear, smashing the Nightsong and dragging her to the depths. Thorm will also make his escape, and you have to chase after him. Before you jump down the chasm, you can ask Jaheira to join the group as a full-fledged companion.

The Mind Flayer Colony

You’re going to experience another brain-filled bonanza because there’s a Mind Flayer Colony underneath Moonrise Towers. The Intellect Devourer brains won’t bother you too much, so you can explore a few rooms:

• There’s a chamber with several pods that contain Mind Flayers and various NPCs, including Zevlor. If you open these pods, the NPCs will assist you, but you need to deal with multiple Squidwards at the same time. If you ignore them, you won’t like what happens to Zevlor later in the campaign.
• The room after that has a pod where the devil Mizora is imprisoned. You can convince her to release Wyll from his pact by releasing her. This is done by passing a Strength check. Conversely, if you pull the left lever, Mizora will die, and she’ll drag Wyll straight to the hells of Avernus (he’ll disappear from your party forever).
• Explore, battle, and loot as you see fit. Eventually, you’ll see a restoration point. Next to it is an elevator that takes you to the inner chamber. There’s a cutscene showing the three “big bads” of the game: Gortash, Orin, and Ketheric. You also see the Elder Brain–aka. the Absolute–that they have under their control. If Gale is with you, he can self-destruct with the Netherese Orb as part of the Wizard of Waterdeep quest. This is not the intended path, since this only leads to a short cutscene and a game over.

Ketheric Thorm Phase 2.1

In any case, approach the arena to go for round two of the Ketheric Thorm boss fight in Baldur’s Gate 3. You’ll need to be aware of the following:

• The Nightsong has been chained in the back section of the arena. You can use a character with high movement range or teleportation to reach her quickly. You can then free her via the Help action. She can DPS Thorm for most of the encounter.
• You have to contend with Mind Flayers, as well as Thorm’s Incubate Death spam. This turns into a battle of attrition since numerous Necrolites will be spawning, and you have to deal as much damage as you can to the boss.

Ketheric Thorm Phase 2.2

Once you deplete Thorm’s HP, he’s not done yet. Well, he is the Chosen of Myrkul, the God of Death, so he won’t be that easy to kill. He’ll reemerge as the Apostle of Myrkul, a skeletal giant with deadlier abilities:

• The Bone Chill aura remains active, preventing characters from getting healed. This also applies to reviving downed characters via healing spells.
• The monster can consume a Necrolite, granting it the Finger of Death spell. It’s basically a one-shot-kill ability due to the high damage in a single hit.
• At best, you just need to pump out as much damage within a short span of time. Lingering/concentration AoE spells like Spirit Guardians, Moonbeam, and others are also viable.

Boss Fight Rewards

If you manage to defeat Ketheric Thorm in Baldur’s Gate 3, you’ll earn the following rewards:

• Ketheric’s Warhammer – Deals 3-15 damage; +1 enhancement; also does 1d4 psychic damage.
• Ketheric’s Shield – +2 armor class; +1 spell save DC and attack rolls; can do a Shield Bash as a reaction to knock enemies prone.
• Reaper’s Embrace – +19 armor class; reduces all incoming magical damage by 2; cannot be moved against your will but gives a disadvantage on Dexterity saving throws; disadvantage on Stealth checks; Howl of the Dead cantrip.

Moreover, you’ll acquire Ketheric’s Netherstone. This is one of the three quest items that control the Elder Brain (the other two are held by Orin and Gortash). Lastly, there’s a letter from Iz… and it’s revealed that the Cleric Isobel is actually Thorm’s daughter.

In any case, that concludes this climactic battle for Act 2. With the army of the Dead Three on the move, it’s time for your group to head to the city of Baldur’s Gate.