Blades:A Tale of Two Brothers

Quick Walkthrough
 
# Speak to Saashi.
# Follow the ghostly figure to reach Valentis' tomb.

Detailed Walkthrough
Speaking to Saashi in town near the Main Gate will yield your motivation for reentering the crypt below the broken Ayleid statue: 
:"Good news! This one managed to learn the name of the Sorcerer-King: Celemaril Light-Bringer." 
:'''That doesn't sound so bad...
:"Not sure his people agreed with that. His own brother, Valentis, led a rebellion against him. He and the other Ayleid kings managed to stop the Sorcerer-King and bind him magically. Saashi is fairly certain the statue destroyed by the Queen's men was of Valentis. This one has found Valentis' final resting place. Perhaps there are runic inscriptions in the burial chamber... Up for a bit of tomb robbing?"
:I'm on it. 
:"Good. Saashi cannot wait to see what there is to be found!"

Saashi will be in front of you at the entrance to the burial chamber. Speak to her again and she will give you a little more information: 
:"This tomb looks a lot like the Sorcerer-King's, does it not? It does make sense. They were built during the same era, probably by the same architects. It certainly is just as... creepy." 
:You stay here, it's safer.
:"Saashi will follow from a distance, and meet   in the burial chamber." 

During the conversation, a ghostly figure, presumably Valentis, waits at the far side of the room near the exit. Approaching him causes him to flee, and chasing him runs you directly into a forest spider. There is a health-restoring mushroom patch at the base of the following stairs. Keep heading downward to defeat a wight and skeleton guardian. The ghost will again flee, but check the room before you follow: there are three samples of limestone on shelves, two urns to break for loot, and a chest to collect.

Enter the next hallway for another battle against a spider. The room at its end has two more wights, but also significant loot. Check for three more urns, another chest, and a glowing mushroom health restorative. On one of the columns there is a button, which gives access to the secret area''' of the dungeon. The far side of the room is barred by an Ayleid door, through which you can see the ghost waiting for you to catch up. He flees immediately upon opening the door, but is replaced by a skeleton guardian. Once you defeat it, keep heading downstairs to a room with a forest troll, an urn, and a chest.

Further down, you'll find the ghost waiting eerily in a patch of light near mushrooms. Past him, you'll enter a cutscene with Saashi speaking as you look around the tomb. 
:''"You did it,  , you found Valentis' burial chamber. This mural, it's...mesmerizing. Look, there's the Sorcerer-King! And this relates to how Valentis fought back his brother's undead forces. Here he is shown binding the Sorcerer-King in his tomb...somehow. Let's copy those runes and go...I feel like someone's watching us." 

Stepping into the room will trigger quest completion. There is no loot, but you can choose to explore for a closer look at the mural. 

After returning to town, Saashi will be excited to have made progress: 
:"That was quite the adventure, was it not?"
:Nothing we couldn't handle.
:"This one had time to look over the tablets while we were traveling back here. Come speak with this one when you’re ready to hear what has been found, yes?"''
 

Enemies
Forest Spiders x 2
Skeleton Guardians x 2
Wights x 3
Forest Troll x 1