Ruined planets are post-endgame planets explorable only once the final boss has been defeated. They are planets that once cultivated vast quantities of life and as such were decimated by the Ruin. The dificulty of the planet itself would be the same as the Ancient Vaults if not harder. Upper Biomes: Tentacle (returned from beta), Alien, Hive. Resources: Aegisalt, Ferozium, Violium, Solarium Enemies: Ruin spawns along with Alien and Hive based spawns (Health and damage scaled for difficulty) Encounters: Cultists (Hostile), Chests containing Cultist equipment Environmental Hazards: Radiatic Rain - Potent acidic rain that radiates players. Turning them green and preventing any form of healing as long at their health is above 15% of their maximum. MISC: There are vast empty canyons on Ruined planets that once housed large amounts of liquids. These can be as large as the craters on moons, so take caution lest you die to fall damage. Lower Biomes: Heck (returned from beta), Flesh, Slime, Brain (in very small patches, never a full biome) Core: Dead (No fragments) Anything associated with the above biomes. "With the Ruin gone, it's now safe to explore the planets left in its wake. These "corpses" of planets contain vast quantities of useful resources, but exploring them safely will prove nigh on impossible."
Interesting idea you got there o: I'd suggest to go even further: why not a miniboss of some sort at the planet's core?
They could be in the scrapped Nebulas that would've been endgame "star systems" that contain all planet types, with each planet having a sub-biome being the Ruin. I'd say they could also have Tentacle Meteors weather events, where Tentacomets fall to the planet and act as minibosses.
