In your quest to complete the Sinnoh Pokédex in Brilliant Diamond and Shining Pearl, you will have to seek out Mesprit, Uxie, and Azelf: the Beings of Emotion, Knowledge, and Willpower.
Before you set off on your hunt, make sure you have first completed the Mt. Coronet section of the main story, with Dialga and Palkia.
Naturally, save your game before taking on these Legendary Pokémon.
Where to find Uxie in Brilliant Diamond and Shining Pearl
In order to find Uxie, head to Acuity Lakefront. You'll find this west of Snowpoint City.
As with the other Lake Guardians, use the Hidden Move Surf to get onto the water, then find the Acuity Cavern at the centre of the lake.
Uxie is found inside. It's much easier to catch than the other two, but be prepared to hurl plenty of Ultra Balls at it.
How to capture Uxie in Brilliant Diamond and Shining Pearl
Before you take on Uxie, pay special attention to your team composition. Uxie is a Psychic-type Pokémon, and is pretty strong.
Absol is a very useful choice, with Dark-type Pokémon being immune to Psychic moves. It can also learn False Swipe through TM54.
When it comes to Poké Balls, we recommend trying the following alongside those Ultra Balls.
- Quick Ball at the start of the fight.
- Dark Ball, ideal for catching Pokémon found at night or in caves.
- Timer Ball if the fight drags on.
Of course, you could always just use a Master Ball... but that's no fun, is it?
Happy hunting!