Castle Thorn Dungeon Guide

“Despite Lady Thorn’s mysterious past, the Ravenwatch never felt the need to deal with her directly. She seemed content to hide away in the mountains, alone in her horrific castle. This one wonders if ignoring her was a terrible mistake.” —Adusa-daro

Castle Thorn is a four-person dungeon in the game The Elder Scrolls Online. The dungeon consists of various rooms and corridors, each with its own challenges and enemies.  Castle Thorn can be accessed at Level 45.  In this guide, I shall explain the mechanics as well as what you should and shouldn’t do while facing the dungeon’s bosses.

Castle Thorn Location

Castle Thorn is located in the western region of Western Skyrim.  Travel southwest from the MOr Khazgur Wayshrine to reach Castle Thorn.  You can also access Castle Thorn specifically by using the Dungeon Finder.

Inside Castle Thorn

Castle Thorn is a four-level dungeon with five bosses and one quest.  The enemies in this dungeon include death hounds, Thorn Legion Maulers, bloodfiends, and hemopteras.

Blood of the Past

Gwendis arrived at Castle Thorn to investigate a story that Lady Thorn has started amassing an army. She wants to know what the lady is planning and asked me to help uncover it.

Completing Blood of the Past

You will need to defeat Dread Tindulra, Blood Twilight, Vaduroth, Talfyg, and Lady Thorn. Speak to Gwendis to complete this quest.  Completing this quest will reward you with gold, a skill point, and an Unidentified Castle Thorn Armaments coffer.

Castle Thorn Boss Mechanics

Need specific info?  Click these quick links to go directly to each section.

Dread Tindulra

This boss is pretty basic but for an early boss can be a bit of a PUG killer! The tank should turn it away from the group at all times while maintaining a static position where possible. Running around the room will make this messy very quickly. So hold your ground as a tank unless you avoid standing in stupid.  The DPS and Healer should be behind the boss and stand where ever is safe. Be sure to NOT run around the room in circles as the boss does NOT like it and people will suffer from it.

Bite/Fire Balls – The boss hit with basic bite attacks but while at range will spit fireballs instead. Block these if they hit you but they should really ONLY be on the tank. So a taunt MUST be maintained.

Fire Breath – This is pretty self-explanatory, the boss breathes fire in the direction of the tank or whoever has the aggro at the time. Don’t stand in this. If you are the tank you can block it, but it does hit pretty hard.

Fire Puddles – The boss will spit fire into the air and it will land in many different places on the floor. usually aimed at people directly so when these attacks happen, be sure to step out of them. They will remain burning on the floor and take up a lot of space. Do NOT stand in them!

Big BOOM! – The boss will STOMP on the ground. When this happens ALL Fire AOE puddles on the ground will explode. If you are standing inside one when they go boom, you die! Don’t stand in them!

PIN/Charge – The boss will occasionally charge a member of the group to knock them down. Usually the furthest away. If you are charged be sure to block it.  Occasionally however this is not just a charge but a FULL knockdown pin. The boss will continuously bite the player until they are dead. You MUST help by interrupting the boss to get them off your teammate before they are killed!

Adds – After 75% the boss will occasionally howl. When this happens, multiple mini dogs will come into the fight. The tank should pull these in and control them while the group kills them. Be sure to get rid of the adds so you are not overwhelmed. If you are dps/healer and you have aggro of these do NOT run around the room, try to maintain your composure and keep doing what you are doing, block if necessary while the tank gains aggro on them. Running around makes you susceptible to the charge mechanic more often due to your distance from the boss.

Blood Twilight

This boss is very simple in terms of mechanics but it is very easy to make a mess of it if people panic. If you are following mechanics rather than “nuke it or go home” there are some very simple rules to follow. The simplest way to tank the boss is to drag it into a corner and face it against the wall. Then the dps/healers should stand behind the boss at all times.

Heavy Attack – The boss will disappear and then jump in on the tank with a heavy attack, much like the Shadow Strike type ability most Twilights do, including the bosses from Maw of Lorkhaj and Imperial City Prison. The tank simply needs to block this.

Machine Gun – This barrage of damage is the same as lord warden. He will fire multiple magical attacks like a machine gun and the tank needs to block this/stand in front of it until it is over. Absorption skills also work.

Imps – Four Imps will spawn around the room. The tank can pull these in OR the group can go off and individually kill them, but either way, you want them dead. While they are alive the boss will be buffed and hit harder.

Blood Phase – After the Imps have spawned, the boss will teleport into the middle of the room. He will be immune to damage and the group must stay OUT of the blood or die. Pull the boss back to the original position once the phase is over.  However, during this phase, an add will spawn (see below) and also multiple ghost/spirit-type reflections of the boss will appear and suddenly wing-slap the group.  This is a very simple mechanic. BLOCK it, or get thrown into the middle.  Once the phase is over, simply carry on as normal.

Reanimated Vampire – During the Blood phase and having to block the wing slaps, you will have this add spawn. The tank must taunt it and turn it away from the group as it has some rather heavy-hitting cleave attacks with his two-hander weapon. This is now your primary target.  Kill this add with full focus on it, even if the boss blood phase is over and now back in the fight, you MUST focus on this add. Getting overwhelmed with multiples will make a mess.  The rest of the fight is rinse and repeat with NO enrage mechanics.  If you can do one phase, completion is inevitable because the rest are the same. It’s repetitive.



With this boss coordination is key. If you don’t work well as a team this can get messy fast! You have already seen most of the major mechanics if you have gotten this far so you should be fine, but this is where it all gets put together at once.  The tank should maintain a taunt, hold the boss still and turn it away from the group at ALL times.

Heavy Attack – The boss will attack whoever has aggro (should be the tank) with a huge swing of his Scythe. The tank MUST block this. If you are a dps/healer and this is going to hit you, dodge roll it. You won’t live trying to block this as it is designed for a tanky character with block mitigation bonuses.

Swarm –  During the fight, the boss will select a target and a swarm of crows will chase them. This circle AOE will cause HIGH damage if caught inside of it. The player affected should take it out of the group and kite it around the room in a safe place until it is over.

Scythe Throw – at 75% 50% and 25% the boss with throw his Scythe across the room and it will draw in ALL players. Each player will have an aoe under their feet with a rapid timer on it before it explodes. When this happens you MUST co-ordinate as a group and agree on who is going where! Basically spread out ASAP so that NO ONE overlaps. If you are all safe, the explosion will go off and you can continue as normal. If anyone overlaps, they will die!

NOTE:  After this, you can attack the Scythe and then throw it at one of the hanging bodies to release some mini pets to help you in the fight.

Reanimated Vampire – After each throw phase the boss will spawn a Reanimated Vampire, much like the one in the previous boss fight. The mechanics are exactly the same and you MUST focus on it. If you do not prioritize this target and you end up with multiple by overburning the boss and not the add, you will be in some serious trouble as these hit very hard.

Summoned Goo! – Periodically throughout the fight the boss will also summon a purple ball of goo. It will attack players from range. Be sure to kill this as soon as you can. And continue on the boss once it is dead.

KEY Points:  Coordinate with the split mechanic, and always focus adds over the boss.


This boss is simple if you apply basic mechanics and awareness. But if can be hell if not. The tank should hold the boss at ALL times as still as possible unless they HAVE to move. This is simple, “hit the boss, hit the adds, back to the boss again” fight. Not hard really in essence but some mechanics will wipe the group quickly. So pay close attention.

Heavy Attack – The boss will throw out occasionally at the tank. Simply block this and you will be fine.

Ground Pound – The boss will occasionally smash the ground leaving a large aoe on the ground. You can block this as the tank but be sure once it has landed that you step out of it. DPS/Healers do not want to be anywhere near this!

Gargoyles – Throughout the fight, the gargoyles from the sides of the room will spawn and slowly walk toward the boss. They hit pretty hard and have nasty growing AOE damage around them. be sure to focus these down as soon as they awaken. If you leave them to come to join the main fight then the tank will get overwhelmed with a LOT of damage and it just makes a mess.  Get off the boss, kill the awakened gargoyles, then get back on the boss again. Simple focus-based mechanics of prioritizing targets.

BEAM! – The boss will aim a beam of damage with a ground-based aoe attached to it. The tank can block this or simply step out of it.

GROUP BEAM! – At LOW health (after all of the gargoyles have been awakened and the boss is approaching low health) the boss will raise his hand in the air. When this happens the entire group needs to split up and go in different directions to kite the beam away until it is over. Once the mechanic has finished, come back in and fight the boss again. IF you fail this you will die. It does massive damage, doesn’t get caught (demonstrated in the video).  This mechanic at low health will repeat over and over until the boss is dead so pay attention to his actions.

Lady Thorn

This boss is very simple BUT hit’s like a truck. So there are some CLEAR mechanics that you MUST pay attention to. The tank should hold the boss as still as possible at all times while the group stays relatively CLOSE but behind her. If you spread out too much too often she will make things very difficult.

Heavy Attack – The boss will heavy attack the tank, this is a BIG hitting ability and MUST be blocked. no block = dead tank, you WON’T survive.

Bombs – The boss will cast multiple bomb-type aoes on the ground. Step out, get away from them, and come back in again. nice and simple, don’t mess it up or they will kill you fast!

Bat Swarm – The boss will disappear leaving a HUGE aoe on the ground of swarming bats. If you TOUCH this you will die. In the meantime, multiple smaller swarms will shoot OUT from it and then come back in again. Do not let any of these touch you as you will take HUGE damage. And in the meantime, 3x small zombies will appear. Simply kill these and then carry on as normal.

Note:  When the phase is over she will spawn on a player of her choice with a LARGE aoe burst on the ground. Get out of this and don’t let it hit you or you will die (70k+ damage in one hit).

Teleport Punch -This mechanic is simple but fast. She will dash across the floor and hit one player of her choice (usually the furthest away but not always so stay close and maintain your positions). If it is YOU she is aiming at. You have two choices. BLOCK/DODGE and live…don’t and DIE!

In the Light! – At 60% and at 20% the boss will be immune and a big circular light aoe will appear. The rest of the Room is a bat swarm. If you stay in the bat swarm you will die, if you stay in the light you will live.  While in the circle it will move around and you must stay with it, but the boss will charge the group. You can dodge this attack or block it, but if you are HIT you will be stunned/knocked down and have to break free.

During this entire phase, periodically a Guardian add will spawn. This must be killed and interrupted occasionally to avoid its channeled attack. And the tank must maintain the aggro of it. Make this target your main focus, it MUST die, you don’t want multiples.  Also during this phase, SCAMPS will spawn. These are very low health but when they die they drop a synergy on the ground.  Take the synergy 4x and the boss will come down and you can continue the fight as normal (the phase is over).

NOTE:  The synergy will allow you immunity to the bats for a couple of seconds if you run out and grab it but be sure to get back in the light fast.  Also note, on hard mode you will have multiple Zombies in the room too.  Once the phase is over it is rinse and repeat until 20% and then rinse and repeat until dead. There is NO enrage and NO dps check.

Hardmode Execute Phase – After the second light phase at 20% is over. The room will REMAIN in darkness. The light will remain also! Now you must fight the boss, while on the move! She will have her BASIC mechanics and bombs.  No dps check, no enrage, just watch your feet and kill her.


Castle Thorn Dungeon Loot

Below is a list of all the loot you can expect to find in Castle Thorn.

On normal the loot is blue and the boss does NOT drop a monster helmet, but on veteran difficulty all of the loot is purple and the main boss DOES drop a special monster helmet.

Note: in dungeons some individual bosses can drop a unique item but generally, the weapons and jewelry (non-named items) come from the last boss. HOWEVER the entire loot table can also drop from trash and chests, so loot everything!  Got the gear in the wrong traits?  Don’t worry!  You can alter the traits by either transmuting or reconstruct the piece with a trait of your choice.  For more information see the Introduction to Transmuting and Reconstructing article.

If you are looking for a matching shoulder monster piece, visit the Undaunted Pledge Master Urgarlag Chief-Bane at the nearest Undaunted enclave.  She sells a 50/50 chance at the shoulder piece as part of the Stonethorn Coffer or it could be in her mystery coffer.  You can learn more about the Undaunted in the Undaunted Guide.

Builds That Use Castle Thorn Gear

ESO In-Game Icon Gear Firesong Circle Heavy Chest A
ESO In-Game Icon Weapon Sword

Castle Thorn Achievements

ESO In-Game Achievement Update 27 Dun 2 Perfect
Bane of Thorns

Defeat all encounters in addition to Dread Tindulra, the Blood Twilight, Vaduroth, Talfyg, and Lady Thorn after raising the challenge banner in Veteran Castle Thorn within 30 minutes without suffering a group member death.

ESO In-Game Achievement Update 27 Dun 2 Meta
Castle Thorn Conqueror

Defeat Dread Tindulra, the Blood Twilight, Vaduroth, Talfyg, and Lady Thorn in Veteran Castle Thorn.

ESO In-Game Achievement Update 27 Dun 2 Vet Bosses
Castle Thorn Conqueror

Defeat Dread Tindulra, the Blood Twilight, Vaduroth, Talfyg, and Lady Thorn in Veteran Castle Thorn.

ESO In-Game Achievement Update 27 Dun 2 Bosses
Castle Thorn Vanquisher

Defeat Dread Tindulra, the Blood Twilight, Vaduroth, Talfyg, and Lady Thorn in Castle Thorn.

ESO In-Game Achievement Update 27 Dun 2 Flavor c
Four by Four

Defeat Vaduroth after each group member bursts at least one imbued hanging corpse with the sickle in Veteran Castle Thorn.

ESO In-Game Achievement Update 27 Dun 2 Flavor g
Guardian Preserved

Defeat Lady Thorn after raising the challenge banner without killing the Blood Guardian in Veteran Castle Thorn.

ESO In-Game Achievement Update 27 Dun 2 Speed

Defeat all encounters in addition to Dread Tindulra, the Blood Twilight, Vaduroth, Talfyg, and Lady Thorn within 30 minutes of entering Veteran Castle Thorn. Your timer starts when you engage the first group of enemies.

ESO In-Game Achievement Update 27 Dun 2 Flavor a
Hound Pound

Defeat Dread Tindulra and kill her Broodlings while they are at least 15 meters apart in Veteran Castle Thorn.

ESO In-Game Achievement Update 27 Dun 2 Deathless
Impervious Onslaught

Defeat all encounters in addition to Dread Tindulra, the Blood Twilight, Vaduroth, Talfyg, and Lady Thorn in Veteran Castle Thorn without suffering a group member death.

ESO In-Game Achievement Update 27 Dun 2 Flavor e
Let Sleeping Gargoyles Lie

Defeat Talfyg without killing any of the large Frozen Gargoyles during his encounter in Veteran Castle Thorn.

ESO In-Game Achievement Update 27 Dun 2 Flavor d
Sickle Skills

Burst 70 corpses using any of Vaduroth’s Sickles in Castle Thorn.

ESO In-Game Achievement Update 27 Both Dun Vet
Stonethorn Delver

Complete both Stone Garden and Castle Thorn in Veteran.

ESO In-Game Achievement Update 27 Loyalty Reward
Stonethorn Explorer

Enter either Stone Garden or Castle Thorn for the first time.

ESO In-Game Achievement Update 27 Both Dun Normal
Stonethorn Scout

Complete both Castle Thorn and Stone Garden in Normal.

ESO In-Game Achievement Update 27 Dun 2 Flavor f
Taking Turns

Defeat Lady Thorn after completing both bat swarm phases where each player used the Blood Scavenger synergy at least once per phase in Veteran Castle Thorn.

ESO In-Game Achievement Update 27 Dun 2 Kill Monsters b
Thorn Legion Senche-Raht Slayer

Defeat 50 Thorn Legion Senche-Rahts in Veteran Castle Thorn.

ESO In-Game Achievement Update 27 Dun 2 Kill Monsters a
Thorn Legion Slayer

Defeat 200 Thorn Legion Vampires in Veteran Castle Thorn. This includes Thorn Legion Sanguimancers, Quickblades, Marksmen, Maulers, or Reanimated Vampires.

ESO In-Game Achievement Update 27 Dun 2 Final Boss Hard Mode
Thorn Legion Style Master

Learn every chapter in the Thorn Legion style book, occasionally found as rewards for completing the Castle Thorn Dungeon.

ESO Icon Achievement 024
Thorn Remover

Defeat Lady Thorn after raising the challenge banner in Veteran Castle Thorn.

Castle Thorn Leads

There are currently no leads located in Castle Thorn.

Final Note

Thank you for taking the time to watch the content and read this guide. Be sure on your travels to remember, although once you get very experienced you may make these dungeons much easier and faster… it starts from the ground up and it’s…