well .. I undestand the need to include "pedia" although it could be its very own word. Like Elementology, for instance.
for instance, if a Morrowind/Oblivion TBS game were to come out, the pedia would most likely be called "the elder scrolls"
wether the name for the pedia will be closely tied with the games main name will have to be up to the development team.
"Of the Elements" would actually be a decent name for the Pedia, as refers to the game's title, is not akward to say, and references the fact that it is indeed an encyclopedia of the game.