Eternal Ruins is one of the six dungeons set aside for jobs titled Legend of the Mysterious Ruins in Pokémon Mystery Dungeon: Gates to Infinity. These dungeons are mostly available for Multiplayer with other Teams through Local Play but can be taken in single player Mode with only one Pokemon to go in the Dungeon. All of these dungeons consist of only one floor, meaning that anyone who enters the dungeon is immediately cast into a boss fight. This Dungeon can be played through three different levels of difficulty depending the amount of Red Stars the mission has, each level with how powerful the boss is and what move sets it has. Rewards for completing the dungeon often include (but are not limited to) Heal Seed, Vile Seed, Gold Ribbon, and various scarves, bands, seeds, and Materials.
Recruitment is not possible in this dungeon.
Ho-Oh or Ho-Oh (Shiny) (1F)
For the first time in the Mystery Dungeon Series, the random encounter of the shiny form of any Pokémon can appear. in this case, it is only the shiny form of Ho-oh that appears in Gates to Infinity. When shiny Ho-oh appears, it has the sparkle effect like most of the Pokémon games when a shiny appears in battle. Be aware that the shiny form of Ho-Oh is stronger than the normal form of Ho-Oh, with more stats and different move sets that make this Pokémon more challenging.