Floating islands

Floating Islands in Mirosia are chunks ripped out of other planes by Portals.

Types of Floating Islands
A variety of different kinds of floating islands exist. The Cartographers' Guild in Mirosia has attempted a loose classification system for the islands, but every island is unique, and not all of them will fit into clean-cut categories.

Seabound vs. Skybound
Islands in Mirosia can float in one of two fashions - some islands are "seabound", floating on top of the oceans of Mirosia. Others are "skybound", able to float independently, drifting in the sky.

Flotation in both instances is due the formation of Levia Dragonshards, crystallizations of magic that occur during the opening of Portals. These dragonshards repulse the ground, enabling flotation. The weight supported is proportional to the size of the dragonshard, which means that large ones will lift an island up higher or support a larger island. Islands with insufficient supplies of Levia dragonshards will become seabound or even sink beneath the waves.

Categories
The following are major categories of island, organized from roughly lowest to highest rarity.

Prime Material Islands
Ripped from various prime material planes, and the most common variety. One could find virtually anything here, from a kobold tribe hidden in a dragon's lair to a wizard's tower. Natural biomes define the terrain of these islands.

Asteroid Islands
Usually not true "asteroids" in the outer space fashion, these islands are ripped out from the underground of the prime material, rather than from surface levels of a plane. They are more likely to be home rich mines, dangerous and bizarre monsters, drow enclaves, and dungeons and tombs of old.

Elemental Islands
Ripped from the elemental planes, these islands are home to elementals in Mirosia, and each reflects it's home plane in it's own way. Most represent the primary four elemental planes, but some islands have manifested from the various mixed elemental planes that hold combinations of forces.

Feywild Islands
These islands are the most unpredictable in terms of what one might find upon them - the feywilds are home to creatures across the moral spectrum and home to many different creatures and cultures. These islands can range from harmless to deadly, all depending upon the nature of the creatures who reside upon them.

Shadowfell Islands
Ripped from the Shadowfell, these creepy islands are often home to hoards of zombies, undead, even vampires. An aura of darkness still seems to surround them, and they are among the worst active threats to Mirosia, because some of their inhabitants will actively plot against the island. A few have even gained some control of their islands flow through the winds, creating a truly dangerous enemy.

Lunar Shards
Ripped from the moons of other worlds, these islands are amongst the strangest of all. Alien aberrations make their homes upon them, and proximity to a lunar shard is a trigger for those infected with lycanthrophy.

Mechanical Wonders & Clockwork Contraptions
Buildings and contraptions ripped from the plane of Mechanus. Somehow pulled through in perfectly working order, these mysterious mechanical islands have a myriad of functions, and no two seem the same. Some are perfectly safe, while others are dangerous in the extreme. These islands are always skybound, and can float without Levia dragonshards.

Limbo Fields
Ripped from the Plane of Limbo, these fields of energy are full of swirling chaos. They could contain almost anything, including slaads, and are prone to Wild Magic surges and other random and unpredictable effects. Thankfully, they are as rare as they are dangerous. Their nature rips apart Levia dragonshards, but they float independently nonetheless. Limbo fields change direction and altitude at random, and can thus pass under the sea and rise up from underneath, making them particularly dangerous when caught unawares in this fashion.

Island Movement Mapping
The Cartographer's Guild is responsible for tracking the motion of islands. This is largely done with ships, as the mists throughout Miriosia shorten long range sight a great deal, making telescopes and other navigational instruments less useful.

The Cartographer's Guild insists that the best way to track island movements is by using a hex-based grid, which Mirosia sits at the center of. They issue an update on map positions once every two weeks on average, sometimes taking a little longer if circumstances require or little has changed.

Island Collisions
It is occasionally inevitable that islands will collide in the skies or seas of Mirosia. In that case, almost anything can happen. Results range across the board. Some are peaceful collisions where the islands merely bounce off each other, allowing the occasional creature to cross over, or even sometimes an infestation of elementals or undead creatures. At times one island might damage another or even knock it out of the sky. Other times islands stick together, creating crazy combinations. The worst case scenario seems to be a collision with a Limbo Field, which may result in slaad infestations, random mutations in native creatures, or even damage to Levia crystals, which can send an island plummeting to the waters below.