Requisite Royal Regalia: It comes in four parts, each a pair of items, one for the Emperor and one for the Empress: the Crowns, the Keys, the Seals, and the Swords.
Crowns: There are the official Great Crowns of the Empire, of course, great heavy things in the shape of entwined dragons of five different metals, with eyes of black opal, and pearls and shining iöseraz in their mouths.
Of course, they have the slight disadvantage of being bloody heavy, and so are brought out only on formal occasions, by which I really mean occasions formal even by the standards of the Court of Courts. The rest of the time, the Imperial Couple wear their working crowns, simple braided circlets of platinum and (red) orichalcium.
(It’s the orichalcium that makes it Imperial, of course – while being able to cook the stuff up in alchemic nucleus-rearranging machines these days has brought the price down considerably from the days when it has to be scraped in tiny fragments out of Precursor ruins, and there aren’t any sumptuary laws that would prevent anyone who wanted to from having themselves an orichalcium tiara made, it’s the courtesy of the thing.)
Keys: Possibly the most symbolically important part of the regalia, the Imperial Couple each have a key – as do the President of the Senate and the Ephor President of the Curia, which is to say, the co-equal heads of the Imperial government.
These keys open the locked covers of the master ceremonial copy of the Imperial Charter, penned in exquisitely expensive calligraphy on equally exquisitely expensive pages, which master copy is brought out only when one of the aforementioned notables is being officially crowned, appointed, or otherwise sworn into office by the other two. But most importantly, they signify their function as the primary executors of, and the foremost servants of, the Contract and the Charter.
Seals: Not the privy seals, of course, which the Imperial Couple wear on their fingers like everyone else. This is the Great Seal of the Empire, which comes in two halves, one side each, and is rather larger than most privy seals, by nature of the significance of the thing. (It’s also rather larger than most organizational seals, but then, the Empire’s rather larger than most organizations.) It’s a big chunk of gold, mostly unornamented, and a little worn. It is, after all, a working seal. (And these days incorporates some nifty data-encryption hardware.)
The Seal, however, is not carried by the Imperial Couple themselves – that job belongs to the Imperial Dogs, who wear the halves on chains around their necks when the Seal is not actually in use.
(History does not recall the precise origin of this custom, but knowing Alphas I, it’s a fair bet that it had something to do with the utility of putting the device that could validate all manner of important Imperial documentation in the all-day-and-night personal care of someone who could bite off the hand of anyone who tried to relieve them of it.)
Swords: The Great Swords of the Empire aren’t greatswords, and indeed, are not all that impressive. Simple teirian, one with a wyvern-skin wire-wrapped hilt and one with one of plain leather, and complete with a few nicks and dings that just won’t polish out. That’s because they didn’t start out being symbolic; those are the original working swords of Alphas I and Seledíë III, and both of ’em got more than a little work done in their day.
That’s where they get their symbolic significance from, which probably makes them even more so. (They don’t work much these days, however, although it’s still theoretically possible that they might. They are, however, kept in condition against that possibility.)
(Also, although not royal, the President of the Senate has a large, long-hafted, double-headed axe. It’s sort of like the traditional parliamentary ceremonial mace, except a little more emphatic. Fortunately, since the Guardians of the Senate came into existence along with the Senate, it’s never actually had to be anything more than ceremonial…)