Continuity/Empyrean as a Term

Empyrean is the term for the people that once inhabited Auberean - the Yalaini, Haebrous, Dericost, and Falatacot. There are two contradictory explanations for how this term came to be.

Alatar
The first explanation is that Alatar Locke coined the term. This was revealed through the AC:DM CD Lore, which, in lore terms, is a collection of writings assembled by the Arcanum of Zaikhal. In the piece The Explorations of Alatar Locke, the arcanum wrote that Alatar coined the term Empyrean. In the piece An Explorer's Notes, Alatar himself wrote that he calls the vanished race "Empyrean" and is glad the term has been picked up by others.

Elysa
The second explanation is that Elysa Strathelar deciphered the word from Yalaini text. In the Black Death Catacombs Quiddity Seed Quest, we get to see the following scene play out:


 * Elysa Strathelar says, "Thorsten, come here and look at this paper."


 * Thorsten Cragstone says, "Well, lassie, truth be - I canna read."


 * Elysa Strathelar says, "Oh...well, I'll teach you. But later. This writing is like nothing that I've ever seen before.  It's not Roulean, not any of the scripts of far off lands - not even similar.  I've figured out a way to translate it, though."


 * Thorsten Cragstone says, "Oh? What's it say?"


 * Elysa Strathelar says, "This word seems like it would sound like...'Empyrean'...it's another culture, maybe a culture we can contact for help with the Olthoi!"

The plot of this, as Asheron explained, is that Aerbax is attempted to tamper with the collective memories of critical events of the past. Aerbax thought, Asheron supposed, that it would prove easier to turn the Isparians if they were still slaves of the Olthoi. It was revealed at the end of the quest, and confirmed by Hoshino Kei the following month, that the female voice leading you through the quest was that of the Olthoi Queen killed by Elysa.

Analysis
We can evaluate the authenticity of of each statement on a few criteria:
 * 1) The in-universe sources of the statements.
 * 2) The number of sources for each statement.
 * 3) The date each statement was released.
 * 4) The in-universe date each statement was made.
 * 5) What is the most plausible, or makes the most sense.


 * Alatar:
 * 1) Locke recounts first-hand in his writings that he came up with the term. Later writings by the Arcanum back this up.
 * 2) We have two sources, The Explorations of Alatar Locke and An Explorer's Notes, although both are from the same collection of lore articles and were likely written at the same time.
 * 3) This information became available in November 2001.
 * 4) Alatar Locke's claims were made fairly early. While we don't have an exact date, we can estimate it at some time prior to Portal Year 1.
 * 5) Alatar did not know the true name of the Empyrean, so he came up with a term. Empyrean is a real word, meaning belonging to or deriving from heaven. This makes perfect sense given that Alatar was of exceptional education, and his study and exploration focused on the Empyrean.


 * Elsya:
 * 1) This statement came from an apparition of Elysa, which Isparians were led to by an apparition of the Olthoi Queen, both of which were created by Aerbax in an attempt to harm Isparian collective memory.
 * 2) We have one source, the dialog from this quest.
 * 3) This information became available in January 2008.
 * 4) This statement was made by Elysa sometime while freed human slaves were still living in the underground city. Humans first began to live there in Portal Year -3.
 * 5) It seems highly unlikely that someone would be able to deduce how the word of an alien language would sound based on script. It is also odd that the Empyrean would call their race by an Roulean (aka English) word that happens to describe them, if only somewhat.


 * authenticity
 * 1) Alatar: We have a first hand account from the person who coined the term, and others backing up this claim.
 * 2) Alatar: We have two different sources.
 * 3) Elysa: This information was released more recently, and may have been an attempt at retcon.
 * 4) Elysa: Her discovery most likely occurred before Alatar coined the term.
 * 5) Alatar: The explanation that Alatar created a term to describe the vanished people is more plausible than Elysa determining the pronunciation of a word based on its spelling in an alien script, and that word happening to be an apt description of those people.

Conclusion
Based on our analysis, Alatar's explanation seems to be the most likely one. While Alatar having two sources is debatable, since they were likely written at the same time by the same person, and could be considered one piece, Elysa's claim to being the earliest discovery in-universe is also open for debate, since we do not know when Alatar first arrived in Dereth or began using the term - only that his earliest exploration can be placed at or prior to Portal Year 1. Additionally, both the Black Death Catacombs and Knorr Quiddity Seed quests were less than faithful to the established story.