Athelyn Savil will only grant you the vault key if Vivec has named you Nerevarine (ie, the Journal stage for B8_MeetVivec is set to 50 or higher).
The temple vault is on the lower floor of the Fane of the Ancestors in Necrom.
If on exiting the vault, you find yourself stuck behind the portcullises, the switch to open these is behind the tapestries opposite the vault entrance.
Persuading Banden to accept Savile's burial in the family tomb requires either 40+ Personality, 40+ Speechcraft, Novice or higher rank in the Tribunal Temple, or choosing the response "The prospect of being put to rest here has already helped her a lot. I'm sure she won't harm you."
The Destroyer's Ringlet is in an urn atop a sarcophagus covered with a red cloth in the same room as the central ash pit.
The following Journal ID and Index codes can be used with the Journalconsole command to manually update the quest to a certain point.
The Destroyer's Ringlet (TR_NecMQ_Destroyer)
Index
Finishes Quest
Journal Entry
5
Peakstar told me to meet Caros Cocceius, the burgrave of Old Ebonheart, and ask him if Boethiah is willing to help me find one of the ringlets.
10
I asked Caros Cocceius in Old Ebonheart about the ringlet, and he relayed a message from Boethiah to me: 'Savile Theras is awaiting ruin in the city of Necrom, but there have been complications. Now Savile Theras is teetering on the cliff edge. Be so kind, %PCRace, and give her that little nudge she desires.'
30
Savile Theras was scheduled for processing into the Ghostfence, but the procedure was stopped halfway through, due to my victory over Dagoth Ur and the deactivation of the Ghostfence. Savile's mind must have taken damage when that happened. According to the priest Bilsa Barus, the ghost wishes to go to her family's ancestral tomb. They cautioned me to be careful with her, as she has gone mad and might become hostile when freed from the room.
45
I released the spirit of Savile Theras. She started attacking the guards and me.
50
I have dispatched the spirit of Savile Theras.
55
The priests mentioned that Savile Theras might find peace when laid to rest in her family's tomb. They have an urn that can be used to transport her remains and her ghost along with them.
60
Savile Theras has agreed to enter the urn so that I can bring her to her family tomb. According to the priests it is located east of Alt Bosara.
65
I was attacked by an angry spirit. The priests in Necrom mentioned that the urn might attract them. This won't make this trip to Theras Ancestral Tomb easier.
70
I arrived at Theras Ancestral Tomb and was greeted by the ghost of a relative of Savile Theras. It said that her remains are not welcome here in this state. They want me to release her to the eastern sea to follow Veloth's tracks instead.
75
I convinced Savile Theras' family to let me leave her remains in the family tomb.
85
I traveled to the eastern coast and released Savile Theras from the urn. She peacefully began to make her journey across the sea.
90
I learned the location of Savile Theras's ringlet. It's in an urn placed on a decorated altar in the Theras Ancestral Tomb.
95
I learned the location of Savile Theras's ringlet. It's in an urn placed on a decorated altar in the Theras Ancestral Tomb.
100
I found the Destroyer's ringlet in Savile Theras' tomb. Simine Turethi will be pleased to receive it.
105
I found the Destroyer's ringlet in Savile Theras' tomb. Alvu Sareleth will be pleased to receive it.