Proceed at your own risk.
Probably a builder, a close friend of S who spawned on the other side of the continent when they logged in supposedly.
We do not know what they look like, but they seem to have been a builder.
We also do not know their gender.
- He/she probably friends with S seeing as he seems to know him/her, as in the fifth book he asks where they are. They also seem to be important to the plot in some way.
- Emerillion also has a Vault in the dungeon "Tomb of The Forgotten King" and is very mysterious, Breeze said maybe it was locked up because something couldn't be killed, but could be trapped.