Aldia's Keep

You are now ready to wrap up Lucatiel's quest line. Lucatiel's final appearance is near the entrance of Aldia's Keep. Start from the Ruined Fork Road bonfire and proceed along the middle passage of the forked road, which should lead you to the gates of Aldia's Keep. The gates are protected by a Royal Guard. Defeat the Royal Guard and equip the King's Ring to open the doors. Lucatiel is found kneeling next to the Foregarden bonfire. Exhaust her dialogue and she would gift you her armour set and weapon. Lucatiel's quest line is now complete. After resting at the bonfire, she would disappear.

45. Wrap up Lucatiel's quest line, Dark Souls II: SotFS

Enter Aldia's mansion to trigger Lucatiel's brother to invade you. You don't have to fight the NPC red phantom. Simply run upstairs to the level where a Giant Basilisk is located, enter the room containing an iron dragon statue, and the invader would despawn. Hanging from the statue's mouth is a lever, pulling which would open the passage to the area boss. Before entering the boss arena, find the Ritual Site bonfire, which is hidden behind an illusory wall. The illusory wall is found near a sconce next to the pool of corrosive liquid.

46. Aldia's Keep, Dark Souls II: SotFS

Royal Sorcerer Navlaan is imprisoned behind a magic barrier. There is a lever on the same floor, opposite from his prison, which can be pulled to free him. To initiate and complete his quest line, don't pull the lever. Pulling the lever would trigger Navlaan to invade you at various areas in the game. You don't want him to invade you as his magic attacks can one- or two-shot you.

Notable loots:

• Red Tearstone Ring. On a corpse in a muddied pond, on your way to the entrance of Aldia's Keep. The pond is guarded by an Ogre. When your HP is at or less than 30% of your maximum HP, the ring grants a 20% bonus to your damage output.
• Brightbug. Found inside an iron chest, near a bunch of mirrors on the wall.
• Northern Ritual Band+2. On a corpse near where you grabbed the Brightbug. Useful for a mage build because the ring increases your spell uses by 30% at the cost of reducing 50% of your HP.
• Fragrant Branch of Yore. Dropped by a Mimic that is imprisoned in a cage. The cage hangs from the ceiling.
• Aldia Key. Use to open all locked doors in Aldia's mansion. The key can only be obtained by lighting four sconces. Lighting each sconce would spawn a red phantom Forlorn enemy, whom you must defeat. Leave the sconce on the ground floor to last. After lighting all four sconces and defeating the four red phantom Forlorn enemies, approach the Bone Dragon from behind. The Bone Dragon would let out a thrust attack, then breaks and the Aldia Key would be in your inventory. The thrust attack would most likely one-shot you if you're careless. Inside a room opened by the Aldia Key, there is a lever that would break all cages hanging from the ceiling. Ensure you have defeated all Ogres first, including Ogres imprisoned in cages and the gargoyle, before you pull the lever.
• You require Fragrant Branch of Yore x 3 to unpetrify three enemies, one of which is an Ogre. Save all your Fragrant Branches for now and don't unpetrify any stone statues. Two of the petrified enemies, not the Ogre, drop Bonfire Ascetic x 2 and Elizabeth Mushroom x 2.

Guardian Dragon

Like all Guardian Dragons, this boss is weak against lightning. As soon as it flies upward, run towards its tail to avoid the fire breath. Attack the boss' hind legs, similar to how you fought the Guardian Dragon at Heide's Tower of Flame.

Defeat the Guardian Dragon, ride the elevator up to Dragon Aerie, and talk to the Emerald Herald at the start of Dragon Aerie. She will gift you the Aged Feather, which serves two purposes. The main purpose of the Aged Feather is to function as an infinite use Homeward Bone. The secondary purpose of the Aged Feather is as an item to progress in Navlaan's quest line.