and the aquilaThe Fuuraiken, or the Thunderseal sword, is one of the Outrage weapons created for man to be able to use magic, created by the man named Frederick (Sol). Following the other pieces (or "jinki") of Outrage are the Fuuenken (the Fireseal sword, which Sol stole), the Zessen Fans (in Anji's possession), and possibly others. These weapons were crucial during the Holy War to give mankind a chance against the Gears. Now that the war is over, most of the jinki are returned to the United Nations. Ky is still holding the Fuuraiken (except in Overture).
Given to Ky as a gift for acquiring the new status as leader of the Seikishidan, the Fuuraiken streams bolts of lightning from it's length and stretches it in a wide direction. It can also send out projectiles, making it more useful as a long-ranged combat model. It's fairly long as well, which allows Ky to reach far towards his opponents, so its helpful in terms of "poking".
The Fuuraiken is clearly a prized possession of Ky, as it shows much of his power. As referred in the novel Lightning the Argent, Ky's ability to manipulate the lightning element is difficult to handle, even with the sword in hand. It was also the only hope Ky had to seal away his lover in Overture.
aquilaAfter losing his weapon, he acquired his kingdom's weapon, the 'Aquila', which is practically used the same way as the Fuuraiken, except not only is it long - it has a larger weight, and made of steel. (God, how can he still be able to do his battle position with that thing?) It was intended for decorative purposes, and not for combat, yet Ky apparently had no other weapon at the time. Occasionally, Ky rests it on the ground, though it is more of a way a King should in the course of battle.
One question that pops in my mind is how can Robo-Ky handle his "jinki", if something like the Fuuraiken can't be duplicated. I personally believe it is nothing more than just a weapon, with no real essence in it. It's Robo-Ky himself creating all the magical energies.