|Onix||Rock/Ground||Cave/Dust Cloud||5%, 20% (Dust Cloud)|
Move out into the large open area. On the north side is a man. Feel free to talk to him, but he doesn't want to battle. See the circles to the north, one inside the other? Move onto the centre of the small circle. Okay, here's a bit of a puzzle.
If you want some clues, head through the stone doors ahead and inspect the stone statues at the end. Unfortunately part of the clue will be obscured and you'll need to come back when it's night if it's currently daytime or vice versa to see the rest of it.
But we'll just reveal the answer: From the circle in front of the door, move exactly nine tiles east, then six tiles south. Keep facing south and press the 'A' button. You'll be asked a question. Answer with 'Yes' and the ground will shake.
Now if you go through the stone door, the room will have changed slightly. Head north up to the statue. To either side you'll see a gap between a rock and the wall. Move through one of these gaps and head around along the path until you reach a thin path leading north.
When you do, follow it down to Regirock waiting for you at the end. Interact with it and the battle will begin! As per usual, Save the game before battling the Pokemon, just in case you fail in catching it, assuming you wish to catch it.
Legendary Pokemon Battle - Regirock
Despite being a Rock-type, Regirock only has Electric-type moves to attack you with. So a Ground-type or Pokemon with Volt Absorb or Lightning Rod will be really helpful to absorb damage. Either way, he doesn't hit very hard, but Zap Cannon can annoy you with instant paralysis.
Once you're done, depending on your game, a key will be unlocked. This of course is if you catch the Regi (you need to if you want to encounter the other ones). The Iron Key will be unlocked if you're playing Black 2 and the Iceberg Key will if you're playing White 2.
The Iron Key is used to encounter Registeel, while the Iceberg Key is used to encounter Regice. Let's stay and get us the second Regi, eh? What you need to do is exit out of this area, back to the large cavernous room. There, save and exit the game.
Now you need to re-enter the game. What we now need to do is set the key that you just found so that it's active. Here's how we do it:
- Select 'Unova Link' on the main menu *(4th option)*
- Select 'Key System' in the next menu *(1st option)*
- Select 'Key Settings' in the next menu
- Select 'Mysterious Door' in the next menu
- Select the newly unlocked key so that it becomes active
- Exit back to the main menu and enter the game!
Legendary Pokemon Battle - Registeel/Regice
If you're playing Black 2
If you're playing White 2
Capturing Registeel or Regice is basically the same as catching Regirock. Both Regi only have Electric-type moves at their disposal so Ground-type Pokemon or those with abilities that negate Electric-type moves will be your MVPs here.
After you're done, you only have the other Regi to catch! Unfortunately it's not so easy to get your hands on this one. What you need to do is transfer the key from someone else's Pokemon game of the opposite version to your own . This can be done using the Unova Link Key System.
Once you do, activate that key and repeat what you just did for the last Regi. Use the Regi information above to help you out if you need to. Once you're done with the final Regi, that's all your really need to do!
It is recommended that you get your hands on all three Regis in some way or another (trade or getting the other key). Once you have them all, place them all in your party and you'll be able to awaken the great Regigigas when you encounter him in Twist Mountain . That's the place we should be heading to now!
To get to Twist Mountain, head out the south exit from the large cavernous room. Head south-west to the minecart line, then follow it west over the boulder. When it turns north, follow it in that direction. When you see the Pokemon Ranger to your north, head past her.
Continue on until you reach the doorway at the end. Head on through and you'll be in Twist Mountain!