Doesn't look like there's much to be said about the Emperor, or the Empire itself for that matter. Here's a little blurb about the Emperor at the beginning of the section for FFII:
圧倒的な軍事力で世界を破減に導く、パラメキア帝国の総帥。フリオニ―ルたちに一度は倒されるも、地獄で強大な力を得てよみがえる。
"Leader of the Palamecian Empire, whose military might is guiding the world to ruin. Defeated once by Firion's team, but gains great power in Hell and revives."
Standard stuff. There's a couple of small paragraphs about the locations in Palamecia as well, but it appears to just describe the stuff we already know (e.g., it says Palamecia Castle "can only be approached by airship," etc.).
Don't see anything on the story from the Mysidian Library.
FFII's section as a whole is kind of short and uninspiring. A disappointment, really. This game doesn't get the love it deserves.