Flower Light Palace: Mercurius is the castle where the King of Fiore lives.
Mercurius is an extremely large and tall building, appearing as one of the most visible elements in the valley where Crocus is located, and towering over all of the city's other buildings, with even the Domus Flau located outside paling in its comparison. As evident of its role as the King's residence, Mercurius is a very intricately decorated and designed castle. The place appears to consist a number of different, yet uniform buildings fused together, with some sections protruding outwards and assuming particular forms, and the walls being mainly adorned by orders of large, rectangular windows lined up and flanked by protruding pillars. Its main entrance seems to be a mildly small door topped by a very high decorative arc, which gets pointed near its top, and has its central part adorned by a large, round flower window. To its left is a section keeping its height, topped by another going up high, which possesses a pitched roof, and behind which appears to be a structure reminiscent of ancient Greek and Roman temples, being highly similar to the real Parthenon, near which, to its upper right, sits a part ending in a small dome, topped by a prominent spire; two towers, possessing approximately the same height as the spire, are located on the back and right parts of the building. To the entrance's right, several meters away from it, the building takes on an arched form, with such part being reminiscent of a cylinder partially fused with the structure, soared above by a mildly small spire, almost placed in the back part of the building. Topping the entire castle is a high, round tower, with its lower part, much more massive than the one above it, being adorned by elongated windows and ending in a dome, from which the thinner, top part appears and goes up several meters before ending in a pointed tiled roof.
Mercurius is surrounded by a lush garden, which, much like the rest of the city, is adorned by a large amount of flowers, possessing flowerbeds and, in addition, artistically arranged plants and small, tidy hedges, which have square, hollow spaces on their edges, housing ornately decorated streetlamps, with wavy poles ending in large orbs, with circular objects surrounding them, seemingly floating. The streets there are adorned by mosaics, which consist of a variety of small, flat rectangular stones arranged to resemble semicircles. In front of the palace sits a fountain, surrounded by a ground-level, round and shallow pool; water jets jut upwards from both the fountain and the pool, with the former also housing some plants, or possibly statues of plants, on its base.
Deep underneath Mercurius, to be precisely around the castle prison, there lies an underground space in which, explained by Princess Hisui, is the last place where any freedom was given to criminals and no one ever got out of there. The place is called the Capital of Death, Abyss Palace. Arcadios explains that the reason Abyss Palace is inescapable and became known as the Capital of Death, is because of the Hungry Wolf Knights, the Kingdom's most powerful executioner group, guards the place and executes anyone that was sent there without fail.