Ermor: I suspect you have already read all the description of all commanders (especially summonables) of all Ermorian themes, and the national descriptions of Ermor, Pythium, Marignon and Ulm. There is also information in various descriptions of (Sauromancer, atleast) of C'tis, and Serpent Cult Pythium.
Dom:PPP: There was also that big scenario, where Ermor was the bad guy having special commanders all around the map. Many of the artifacts come from that scenario.
From descriptions of some artifacts I found Great Sarlah, Harakhtor, Shantanok and Vestur of the Black Coven, but there was a fifth one also. Despite being named Kurgi, the he is only one dev's view, the other didn't like Kurgi being named like that. He is something more sinister than just the Harvester of Sorrows or what-was-it.
BTW, how well does Zen's map of Europe go with the old Europe map of Dom:PPP? The new nations couldn't really be fitted on Europe, the world maps does that. But for us old-timers, remake might be interesting. The Black Coven might also be nice, if we got a better map.
I am wondering how well I remember the old nations and their places on the Europe. Here goes a try:
Abysia - Sahara
Atlantis - the Atlantic (:P)
Pythium - Byzantine
Man - Britain
Ulm - Germany
C'tis - Egypt
Arcoscephale - Persia
Caelum - Caucasus? Eastern part of map north from Arcos and south from Jotun, anyway
Ermor - Rome
Marignon - Spain
Pangaea - Poland (or somewhere there)
Vanheim - Sweden
Jotunheim - northern russia
R'lyeh - Mediterranean?
Edit: I really should pre-read these...