Go straight, traverse the mist and light a torch. It's going to be dark ahead.
Light the torch in the hallway. In the next room, there are three Sanctum Soldiers. Lure them out into the hallway and kill them one by one. Reenter the room they came from, and you'll find a new kind of horror: statues that spit a red liquid that can petrify you. Avoid and smash them. Light the torch, too.
There are three holes in the room that lead to your next destination. Approach the hole to right right of the doorway. Beneath, there is a soldier with a bow and arrow and a poisonous soldier. Lock on to each and destroy them with ranged battle. It's also possible to rouse a sleeping soldier. Ring the hole until he wakes up and take him down with a projectile weapon.
Light a torch, drop down the hole and head toward the red light, where you'll be able to stand in relative safety. Light the torch at the entrance to the red offshoot. Pick off the enemies that remain, including a soldier with a bow and arrow and another with a torch across from you. Use projectile weapons to lure them your way and destroy the four spitting lizard statues to give yourself room to fight. If it doesn't go as planned, the safest strategy is still to head for a corner and fight from there.
Make your way around the cave to pillage corpses, where you'll find Bonfire Aesthetic x 3, Brightbug x 2 (which allows you to inflict more damage and receive less) and a chest with Petrified Something x 3. Walk out the only exit, where you'll find four more soldiers, three more lizard statues and more spitting statues. Attract them to you and kill them one by one.
Proceed to the fog door. Don't run, though, because a snake-like creature like those from Black Gulch will make his way out. Destroy him, grab the Alluring Skull x 3 (making sure to avoid the myst from the statue next to it) from the corpse. Kill the last two stone lizard creatures, collect the Promised Walk of Peace hex.
Use a human effigy, summon as many people as you can and split the fight between the three baddies, Afflicted Graverobber, Ancient Soldier Varg and Cerah the Old Explorer. Victory is about numbers and distraction. Gang up on your enemies, taking out one at a time. At the end of the fight, you'll earn Twinkling Titanite x 3, Petrified Dragon Bone x 3 and Titanite Slab x 1.
Walk away from the door where you entered the room and pillage a chest for a Flower Skirt. Don't miss the corpse with the Blackweed Balm x 3, which temporarily increases intelligence, in the same room.
Walk ahead, drop down and reenter Shulva, Sanctum City. Turn left to pillage a corpse for Torch x 5. Walk the opposite way to wind your way out and around the building and into a room with a chest, where you'll find a Dark Greatsword. You can return to the last bonfire with an item or jump out the window where you pillaged the corpse to return to the path leading into Dragon's Sanctum. If you do the latter, keep in mind that you'll need to run out the door, and the momentum will carry you to where you need to be. If you jump, you risk rolling right off of the platform you land on.
Return to the index to continue your journey.