Exploring the caves under Dragonspear castle - Main quest BG: Siege of Dragonspear Guide
Last update: 01 July 2016
This quest consists of two main parts. First you must find entrance to the caves and explore it. This will allow the party to get into the palace basement in which you can find Hephernaan. Both parts are thoroughly described below.
Finding and exploring the caves
Leave the Coalition Camp and select Dead Man's Pass on the world map. Once you reach the location, start moving in northeastern direction. It is best to remain on the main path so that you won't get lost. You must be ready to eliminate two groups of orogs and worgs on your way and one group of Hill Giants. In each of these encounters you must try to eliminate the leaders as quickly as possible - they are most dangerous. Once you reach the corner of the map, open the world map and go to the previously unavailable Underground River (it's on the east from the pass).
Turn east after reaching the new map. Then go to the north. Your destination is a crusaders' camp in front of which you will encounter a few crusaders accompanied by a giant Cyclops. You can try talking with the Cyclops, but in the end you will be forced to attack the enemies. Once the battle starts, focus on healing party members which are fighting with the Cyclops - they will be risking receiving serious damage. Once the battle is won, examine Cyclops corpse and take Seal of Caelar. You will be able to use it in a few places in order to mislead the crusaders. Among these places is Dragonspear castle in which, thanks to the seal, you will be able to perform a small reconnaissance just now (it is optional).
Open the large gate and attack some new crusaders standing on the other side. Select the attack targets wisely as you must defeat a large group of enemies (if you want, you can lure some of them more to the south).
Once the area is secure, select the northern entrance to the cave complex. You don't need to attack the mercenaries and crusaders gathered in the first chamber - no one will recognize you. You can ignore the southern part of the caves (unless you want to explore them very thoroughly) and go immediately to the north. Two sahuagin creatures - Gurgle and Floss - will stop you. If you want, you can try defeating these strong monsters in combat, but it is a better idea to tell them some story and by doing so being allowed to move further. Telling them story is not complicated - simply select the longest dialogue options and don't end the story too early.
Once you get through (with strength or peacefully) you must reach the upper right corner of the map and then turn to the west. Don't bother about the crusader patrols you will pass by on your way, they shouldn't stop your party. Once you reach the western border of the map, turn to the south and reach the place where the Ettin Ghost is located. You can avoid combat by telling the giant that he is a ghost and then promising him that you will find his weapon (The Lost side quest - you don't need to complete it). Go a bit more to the south and you will reach the place marked on the above picture in which you can place the Barrel of Bwoosh! which you received previously from Phoosey.
Now go to the north and you will reach the gate that leads to Warrens location. Sadly, the gate is guarded. After initiating a conversation with Turin Brassbreaker, it is best to shown him the Caelar seal which you obtained from the Cyclops corpse. Then you should hide your true identity and order him to unlock the passage. This will allow you to get through the gate without having to fight an unnecessary battle. Ignore the new crusaders and go north in order to reach the elevator shown on the above picture. It is operated by Einer and Betror who luckily aren't very wise. Select any excuse in order to guarantee the right to use the elevator and reach the Dragonspear Castle Basement.
Exploring the castle basement
Soon after leaving the elevator the team will encounter a group of crusaders led by Belben. Don't count on avoiding the battle even if you show the Caelar seal. Luckily, winning this battle won't be hard (try to eliminate the enemy cleric quickly).
After the battle you must decide how to behave. If you want to find Hephernaan as quickly as possible, then go through the main corridor to the northeast and after reaching the closed gate enter the northwestern room. You will enter the chamber when Hephernaan will be speaking with his master. After a short conversation the battle will start. Focus only on attacking Hephernaan because after receiving enough damage he will escape from there. Then you can continue the battle with remaining enemies (among them wizards Olvenaun and Esserin) or (a better option) you can immediately escape to the elevator.
If during the conversation with Torsin de Lancie in Coalition Camp you agreed on poisoning crusaders' supplies and you received the poison, now you can realize that plan. The water supplies are located in the western room shown on picture 1. In order to poison them you must click one of the barrels and then defeat Water Mephit. Food supplies are located in eastern room shown on picture 2. In this case no one will attack the team after poisoning the food supplies.
If you decided to poison the water supplies or food supplies, then after returning to the main corridor you will be stopped by sergeant of a new crusaders' group. Soon after the battle with crusaders will start, Hephernaan with other mages (Olvenaun and Esserin) will join the fight. You can react to that in a few ways - immediately escape to the elevator; attack Hephernaan, force him to teleport someplace else and then escape yourself to the elevator; finish all battles. The last option isn't recommended if you don't have a very strong party and if you don't have additional healing supplies and spells which will be useful during the escape.
Returning to Coalition Camp
You must return to the elevator which travels between the basement and the caves. You should move there just after you are detected by Hephernaan because the game will allow the party to use the elevator even if the protagonists are chased by crusaders. After returning to the caves a short conversation with Einer and Betror will start. Just like before, select any explanation to get rid of them.
First reach the southern exit from Warrens. Once you're back in the giant cave complex Underground River, start going through the same way towards the exit in the eastern corner of the map. Don't hope that it will be a safe trip - other crusaders will be alarmed and the people you encounter on your way will attack you. Similarly as in case of fights in castle basement, you can decide whether you want to fight all enemies or only the ones that are standing on your way. The largest group of enemies is located in supply point near the cave exit.
Reach the southern edge of the map after leaving the caves. Go back to Coalition Camp after opening the world map. There one of the guards will inform you that the commanders went to the meeting with Caelar Argent in order to negotiate a peaceful solution of the conflict. THIS IS THE LAST CHANCE to complete the side quests in the camp, so make sure that you completed the ones you were interested in.
Select Dead Man's Pass from the world map. You will automatically join the negotiations after arriving. The negotiations will be very linear. No matter whether you agree to give yourself in Caelar hands in exchange for stopping the bloodshed or you protest against the idea, both sides will walk away and start preparations for great war.