TL;DR: I took design aspects from Zootopia's climate systems and fantasy designs from ARK's The Center map to create an awesome flying island cathedral for Fenrir to live in.

So, I was playing ARK: Survival Evolved, playing on the new map, The Center, and managed to finally get a flying mount. As I explored The Center with my newly found mobility, I was astonished when I stumbled upon a floating island in the center of the western most continent. It was breathtaking, and I immediately started thinking of cool ways to implement what I saw into my own story. I wasn't particularly satisfied with how my shrine looked before; it was like I smashed a bunch of Protoss buildings together, a sort of train wreck, really. So a redesign of it came about due to an interesting dichotomy I came up with.

So, the main structure, vehicle, and military production facility of Valhalla (nicknamed The Inferno Forge) is found deep underground. Specifically on the 'hot spot' in the Earth's crust that created the Hawaiian islands. Fenrir's residence is on the mountainous volcano that was growing from the hot spot. He lifted the mountain into the air, and built the Inferno Forge into a cavern so he could use the raw material from the Earth's mantle, separate and refine it, and alloy it with Altorite. The facility is massive, able to produce hundreds of vehicles and units every hour.

Due to the immense heat given off by the molten magma, the Inferno Forge's equipment must be cooled constantly by a massive lake that sits in the caldera of the volcanic mountain that Fenrir lifted off the ground. Water from the lake is constantly drained down a central shaft that leads to cooling pipes that cool the machinery of the Inferno Forge, and once the water has changed to steam, it's siphoned up a venting system and is released from the borders of the caldera lake. The large floating mountain, which has been thus transformed into a beautiful cathedral in which Fenrir calls his home, has vapor collectors built into it, which condense all the water in the air they collect, providing a tranquil waterfall abutment to several gardens, as well as plenty of water to fill a few cosmetic lakes on the surface of the mountain, which in turn, deposit the now-cooled water back into the caldera lake below in regulated amounts. As the cathedral floats so high up, the steam has time to cool, so as not to make the climate upon the floating rock unpleasantly warm and humid. It's high enough that it's kept pleasantly cool while the vapor collectors keep the humidity regulated to be no more than 30%.

So, this floating island, known as The Citadel, has quite a few uses and important functions. It's foremost is Fenrir's base of operations. It's where he and all his friends live, and it houses Valhalla's biggest Altorite crystal, which can be seen floating at the top. This crystal is where the goddess Syn's consciousness resides within, and she controls all of the military units across Valhalla wirelessly through the energy-data network, known as the Syn-Tel Matrix. The crystal, being attuned to other energy production crystals distributed across the forest, is what supplies power to all cities and outposts within Valhalla's borders, and this energy network is unlimited in power output, thanks to Altorite's unique way of producing perpetual energy and transferring it wirelessly to any attuned crystal. The energy signature is also unique in that it can be used to transmit data as well. The amplification nodes found throughout the superstructure of The Citadel boost teleportation signals to reach the furthest outskirts of Valhalla, allowing unimpeded teleportation destinations far outside of the normal range (normal teleportation is restricted to within a power field generated by a local SHARD Tower) and, in fact, end just past Valhalla's outer borders. Lastly, about 50 miles above The Citadel is the junction core of the Valhallan Shield Lattice. The lattice is a system that protects the entirety of the forest from ICBM attacks via multiple floating shield projector nodes scattered across the Valhallan skyline. Its integrity is directly monitored and modulated by Syn via the junction core. The entire system is powered by the commandeered Halcyon space station, Meridian, that beams it's solar collected energy to harvester nodes that feed power to the shield lattice.