Bad Case of Harpies
Twenty years ago, the realm was plunged into civil war when its regent lay claim to the throne after the direct heirs had died under questionable circumstances. After the Duke was exonerated of all charges, he gained the support of the barons of the realm and was proclaimed Emperor. In choosing a Duke to fill the power vacuum, the newly crowned Emperor began consolidating power, beginning with increasing the military strength at the borders. This is the version of history in common memory.
The human deities are formally Greco-Roman, though outside of the Capitol, religion is a more personal matter and many personal deities flourish. Standard non-human deities are available since the other races have been able to work with the humans. I don't mind your Barbie-love, Damon, we know you like it rough :-p As for your character sheet, got the email, but can't open the file. Maybe if you attached it old-school.
The Capitol is in a temperate climate. Since your characters are Imperials, you can pick from Savannah, temperate, dense forest, or mediterranean. The empire has some alpine regions at its very borders.