Corridor of Dark Spirit
Talk to Count Arganan in his office and swear loyalty to him (Left choice). You will receive the Fallen Angel's Sword.
A cutscene in the Castle. The party returns to the Tavern to party it up. Talk to everybody but Syrenne.
If Zael tries to leave the tavern, Syrenne won't let him, so talk to Syrenne (last) to continue the train of events.
Pick both left choices. The party gets really drunk (or so it is implied).
Next morning: Ariel tells Zael that the gang has gone to the castle without him. Head there (or do some more side quests).
Go to the Castle and head to the Count's office. Watch the cut-scene. Exit and head to the Courtyard and examine the device next to the arch where General Asthar is standing. A staircase underneath the fountain will appear.
You can now the lift there to access the Jail (to finish the Starving Kid Quest) as well as your destination, the Underground Depths.
After a scene about the Manipulator's Domain (your next objective) Zael can wander around and talk to the rest of the party.
Only Dagran and Mirania will be joining him however. There is a man standing next to the lift that can upgrade your equipment.
When you're ready, enter the creepy looking portal. The party will arrive in a place much like another dimension.
As Zael makes his way down the path, a large black shadow snake-like thing will move around the area. Open the nearby chest.
The party will reach an area with a hexagonal platform and a robed man kneeling over it.
A cut-scene occurs as Mirania tells Zael not to get close to him. A battle the ensues.
Mini-Boss: Dark Master and Dark Servant
In order to defeat the Dark Master, Zael must use Gathering to make the Dark Servant (a large sword wielding skeleton) appear.
Attack the Servant, and after dealing enough damage, the Dark Master will be vulnerable. Attack him. Once defeated the platform is activated. Use the platform.
The party is taken up to a weird cube like structure, where Zael must Seek to find a gate above the party. Mirania and Dagran will comment that they can't get there. Wait for a moment and Operate the platform, which causes the entire structure to turn. Head for the first gate.
You will encounter the Dark Master and Servant again, as well as two Skeleton Pipers, who will create poison circles.
Take out the Dark Servant, then its Master. Afterward the party can easily clean up the last two enemies. Leave the area and return to the rotating cube.
Activate the platform again, and the party will notice that some magical stairs have appeared. However you are only half way there, so Seek the next gate above the party and activate the platform yet again. Head to the next gate.
The party will encounter another Dark Master and three Skeleton Archers. Repeat the same process as before, defeat all the enemies and head back to the cube room to reset the room's orientation and take the stairs to the next gate.
Another pathway, and right into a battle with a Dark Master and two Servants. Defeat both servants before attacking their master. Continue onward.
Open the chest near the stairs to get an Ogre Nail. Continue to the next chest and save point, and enter the area downstairs.
Another cut-scene starts, indicating the party has reached the 'Manipulator's Domain'.
The only way to hurt shade is via magic/elemental damage. Physical attacks will not affect it. Use Command and have Mirania cast her Plant spells on the Shade, creating a magic circle where Zael and Dagran can stand and attack it. Once a magic circle has been placed, beat on the Shade mercilessly until it dies. Repeat this if necessary.
However, once the Shade reaches less than half of its life, it will possess Dagran. You can either defeat Dagran in order to have the Shade reappear so it can be attacked again. Beat down Dagran as quickly as you can, since he has the same stats as he would normally, which may be difficult. Or the option is to have Mirania cast a Healing Circle and lead Dagran into it.
Defeat Shade as you would normally and receive the Paladium sword.
Another very, very long cut-scene with a stone panel and the Foreigner, as well as the activation of the entire island. The party will leave the Domain and return to the castle. And go through yet another cut-scene, and choose the left option when Earl Arganan asks Zael to activate Ruli Island.
Another short cut-scene with Jill getting really mad at some faceless goons.
Zael gets out of bed and the maid asks him to head to the courtyard. Do so by heading out of the living quarters area and over the bridge to the main area of the castle. Zael can now 'Watch' the island sail through the ocean.
Head down to the second floor. There is a knight (in silver) pacing the area. Talk to him to get access to Chapter 25. He asks you to meet him in the Underground Depths to discuss some troubles he has.
Head out to the courtyard and Zael will be attacked by assassins. In a few moments, a robed figure will join in to help Zael. Defeat the assassins, and the robed figure will run away. Zael will attempt to interrogate one of the assassins, but he will disappear.
Head towards the Military building and go up to the Lookout point to meet with Therius.
Head towards the military building and go up to the Lookout point to meet with Therius. Afterward, Therius leaves, so head back to the military building to see Mirania speaking with General Asthar.
Watch this scene and then speak with Mirania, she'll tell you not to mind it, so head out to the courtyard and speak with Asthar. He will ask Zael if he wants to brave the Tower of Trials. Choose either yes or no. Choosing yes will bring you to Chapter 23.