Several Legendary Pokémon are available in Brilliant Diamond and Shining Pearl, with most able to be obtained in just one version of the game.
One of these, Heatran, is not like typical Legendary Pokémon in that it's not found in Ramanas Park.
How to Unlock Heatran
Once you've beaten Cynthia and become Champion, you'll need to register all 150 Pokémon in the Sinnoh region.
Then, return to Professor Rowan in Sandgem Town, and he'll upgrade you to the National Pokédex.
First up, you'll need to complete the events of Stark Mountain. To reach it, you'll need to trek from Snowpoint City, through the Fight Area, Route 225, the Survival Area, Route 226, and Route 227.
It's a bit of a trip.
As you approach Stark Mountain, you'll come across Buck. After a conversation, he runs off into the mountain.
The first room is quite easy, with a few Strength puzzles. You'll come across Buck in the second room, where he'll join your party.
To find the cave you need, go directly to the right, passing by the path where a rock can be smashed.
Take the stairs a little further on, then the small path on the left with another rock to break. There'll be a pair of Trainers to battle, and then another rock to move with Strength down the path.
Entering the cave, there'll be a scene and Buck will leave.
You can take this opportunity to collect any items, such as those that require Rock Climb, then use an Escape Rope to leave quickly.
Return to the Survival Area and enter the house next to the Pokémon Center.
Heatran will reappear in Stark Mountain, and Buck will announce he's heading back.
Make your way there yourself to encounter Heatran properly.
As always, save your game before the encounter.
Meet Heatran, the Lava Dome Pokémon
Heatran is exceptionally tough to catch, so here's what you need to know.
Like all other Legendaries, Heatran is susceptible to attacks that cause Paralyze or Sleep.
Additionally, try using a Quick Ball at the start of the battle, and Timer Ball if the battle goes on more than ten rounds.
False Swipe is also ideal for lowering its health so that you don't accidentally knock it out, although it will not be very effective due to its Steel type. In addition, its Torch ability prevents it from taking Fire-type damage.
Shiny Heatran
Heatran's shiny form is relatively easy to distinguish.
