From Bulbapedia, the community-driven Pokémon encyclopedia.
The Iron Ruins (Japanese: くろがねのいせき Iron Ruins) is a special room in Iron Island. It is only accessible in Pokémon Platinum, when the player has an event Regigigas in their party. It is called the Iron Ruins because it is the home of Registeel, the Iron Pokémon.
The extra cave is by the exit, and replaces the cave from Diamond and Pearl. A "statue" of Registeel is present. By stepping on the 7-dot pattern on the floor and walking up to the statue, Registeel will attack. It is at level 30. It can be rebattled multiple times as long as the Event Regigigas is in the party; however, it can only be caught once.
| Special Pokémon
|| Only one
| A colored background means that the Pokémon can be found in this location in the specified game. A white background with a colored letter means that the Pokémon cannot be found here.
In the anime
The Iron Ruins appeared in Steeling Peace of Mind! and Saving the World From Ruins!. Unlike in the games, they have no connections to Registeel in the anime, but Dialga and Palkia. Team Galactic conducted experiments at the ruins in order to locate the Spear Pillar on Mt. Coronet, which also caused all of the Steel-type Pokémon on the island to go berserk. When Mars placed the Spear Key into a stone pillar, a beam of energy shot out of the ruins and struck Mt. Coronet, allowing Team Galactic to start scanning it order to locate the entrance to the Spear Pillar. However, due to the efforts of Ash and his friends, the machine used to run the experiment was destroyed when the scan was only 60 percent complete.
Afterwards, Cyrus gave the order to blow up the ruins, as they served no purpose to Team Galactic anymore. As a result, Mars and the Galactic Grunts present were able to escape without getting caught. From a safe distance, Mars tried to detonate the bomb, but Riley and his Lucario used their Aura powers to contain the explosion and move it harmlessly into the sky. Later, Professor Carolina arrived at the site with her research team to conduct her own research of the site.
In other languages