This page explains how to activate the Discovery Room to catch Regirock, Regice and Registeel in Pokémon Brilliant Diamond and Shining Pearl (BDSP).

Where is the Discovery Room?¶

The Discovery Room is accessible via the nearest cave from the entrance in Ramanas Park. To enter the park, you must have the National Pokédex. Inside the Discovery Room, there’s a pedestal ahead where you slot in a Discovery Slate.

Each time you use a Discovery Slate, you can battle one of Regirock, Regice and Registeel and attempt to capture them. The specific Pokémon that appears is random (until there’s only one left). To catch all three, you’ll need a total of three Discovery Slates.

How to Obtain a Discovery Slate¶

You can purchase a Discovery Slate from the bottom vendor inside the Ramanas Park gatehouse. It will cost you 3 Mysterious Shard S or 1 Mysterious Shard L for one slate. To buy three slates, you could exchange–for example–6 Mysterious Shard S and 1 Mysterious Shard L.

Mysterious Shard S and L can be obtained when digging in the Grand Underground after acquiring the National Pokédex. Both are relatively rare, with the L variety naturally being rarer than the S variety. The S variety occupies a 2 x 2 space, while the L variety occupies a 3 x 3 space.

How to Catch Regirock¶

Legendary Pokémon¶

Regirock is the Rock-type titan, excelling in Defense and not much else. The one you’re facing is carrying Stone Edge (can hit hard, but has low accuracy), Superpower (lowers Regirock’s Attack and Defense), Lock On (makes Regirock’s next attack has 100% accuracy) and Zap Cannon (low accuracy, but guaranteed paralysis).

Due to Regirock’s enormous Defense stat and it being resistant to Normal-type moves, False Swipe is incredibly difficult to use in this fight. You could try using X Attack etc. to raise your Attack first. Or look for a Water-type that knows Soak (eg. Golduck or Seaking) to change Regirock’s type.

Besides that, the fight isn’t too complicated. Zap Cannon can be somewhat annoying, so you could field an Electric or Ground-type to avoid being paralyzed. Otherwise, chip away at Regirock and apply your own paralysis before throwing Ultra Balls or, after 10 turns, Timer Balls.

How to Catch Regice¶

Legendary Pokémon¶

Regice is the Ice-type titan, boasting sky-high Special Defense. It has mostly the same moves as Regirock above, but replacing Stone Edge for Blizzard to match its type. Since Regice has lower Defense and doesn’t resist it, you can rely on False Swipe to safely lower Regice’s HP.

Likewise, Regice is more of a wall than a threat, so you shouldn’t struggle to stay alive. But being blasted by a stray Zap Cannon can be a pain. Ground-types are ill-advised due to Blizzard, but Electric-types will be OK as a meat shield. As with most Legendary Pokémon, the best balls to use are Ultra or, once 10 turns have passed, Timer.

How to Catch Registeel¶

Legendary Pokémon¶

Lastly, Registeel is the Steel-type titan, with balanced Defense and Special Defense. Like its brethren, it knows Superpower, Lock On and Zap Cannon; what sets it apart is Heavy Slam. Similar to Regirock, Registeel resists False Swipe. But you can get around it by boosting your Attack or changing Registeel’s type with Soak.

Electric-types are perfect for walling Registeel, as they’re immune to paralysis from Zap Cannon and resist Registeel’s STAB Heavy Slam. When the conditions look good (Registeel has low HP and is paralyzed or asleep), it’s time to liberally throw Ultra Balls or (after 10 turns) Timer Balls.

After Catching All Three¶

Once you’ve caught all three titans, two new slates can be purchased from the Ramanas Park bottom vendor:

• Johto Slate (Brilliant Diamond) or Kanto Slate (Shining Pearl)
• Soul Slate

Additionally, if you place Regirock, Regice and Registeel in your party, you can battle Regigigas at the bottom of Snowpoint Temple in Snowpoint City.