Unown, the Symbol Pokémon, returns in Pokémon Brilliant Diamond and Shining Pearl, and like the original titles, is rather elusive.
To encounter this Psychic-type Pokémon in its many different appearances, players must venture to Solaceon Town and travel to the rightmost side, traversing a puzzle of ledges to locate the entrance to the Solaceon Ruins. The Ruins are home not only to every shape of Unown but in its maze-like halls are very rare items, including Rare Candies and a Mind Plate.
Upon entering the Solaceon Ruins for the first time, players will be able to encounter 26 forms of Unown, one depicting each letter of the alphabet. Each room within the Ruins contains different forms that are not accessible in other rooms, so players should be sure to leave no room untouched to find the letters they may be missing from their collections. Unown is the only Pokémon in these titles capable of using the move Hidden Power, which takes into account the Pokémon’s Individual Values (IVs) to determine the move’s type.
After catching all 26 forms of Unown, a new area of the Solaceon Ruins will become accessible, where players can encounter the final two forms of Unown: the exclamation point and the question mark. This new area of the Ruins can be entered through the Ruin Maniac’s Cave near the Veilstone City side of Route 214. The cave grows in length as the player catches more types of Unown, finally reaching its completion when players capture all 26 Unown forms.
Entering this newly accessible room will enable players to bring their collection of Unown to a complete set of 28, although this does not offer the player any other achievements in-game.