Though there's no sign of Darkrai just yet, the Lunar Duo still has some representation in Pokemon Brilliant Diamond & Shining Pearl thanks to the inclusion of Cresselia. The psychic-type Legendary can be found hiding deep in the post-game and is one of the more difficult and frustrating Legendary Pokemon to catch in the gen 4 remakes. Thankfully, however, there are one or two strategies that can make the task a little less daunting.
The thing that makes Cresselia so hard to capture isn't her low catch rate, nor her immense power, but instead, the way that players actually encounter her in the first place. As series veterans will already know, roaming Pokemon can be an absolute nightmare to track down, and this is once again the case in Brilliant Diamond & Shining Pearl. As in previous Pokemon games though, there are a few tricks that can speed up the process.
Where to Find Cresselia in Brilliant Diamond & Shining Pearl
Before players can catch Cresselia, they'll first need to beat Cynthia and then get their Pokedex upgraded by returning to Rowan's lab after encountering all 151 Pokemon native to the Sinnoh region. The latter may sound daunting, but players should have already seen all but a handful of them by the end of the story, with only Drifloon (return to Valley Windworks after defeating Team Galactic), Lumineon (evolve from Finneon at level 31), and Palkia or Dialga (speak to Cynthia's grandmother in Celestic Town) missing from most players' dexes after a typical run.
Once they have the National Pokedex unlocked, players should make their way over to Canalave City. Upon their arrival, they'll need to stop in at Sailor Eldritch's house, which is on the west side of the city next to the ship. Inside, they'll find the ship captain's son suffering from terrible nightmares, with the game suggesting that Darkrai is the one to blame. After interacting with the sick child, players should head back outside and speak to Sailor Eldritch himself, who can be found standing near the ship just to the right of the house.
Eldritch will explain that he needs to get hold of a Lunar Feather to cure his son and will ask the player to accompany him to Fullmoon Island, to which they should obviously agree. It's only a small island, with one solitary path leading to a clearing in which Cresselia lies in wait. The moment that players interact with her, however, the Pokemon will run away, though does thankfully leave a Lunar Feather behind for the sick child. After returning to Eldritch and Canalave City, players can then begin to prepare for another frustrating chase.
How to Find Roaming Pokemon in Brilliant Diamond & Shining Pearl
Much like the games' other roaming Pokemon, Mesprit, catching Cresselia can be incredibly frustrating. Players will again need to use the Marking Map on their Poketch to keep track of the Pokemon's position, with a view to getting to the same route that she's on and then encountering her in a random battle. She can show up either in long grass or on water and has a very high chance of spawning if players can get to her location before she moves. Sadly, however, the latter is easier said than done.
To speed up the process, players can manipulate Cresselia's movement by repeatedly crossing one of the invisible borders that joins a city with one of its connecting routes. Jubilife City is a great spot for this, as not only does it have four different exits, but only one of these requires players to pass through a building. Once Cresselia does appear on a route connected to Jubilife, players should make their way over to her on foot, save their game and then trigger an encounter either on land or in water. If Cresselia doesn't appear, they should restart the software and try again.
How to Catch Cresselia in Brilliant Diamond & Shining Pearl
If encountering Cresselia weren't already difficult enough, catching her can be an absolute nightmare. Her first action will always be to run away, meaning that players will need to act decisively if they want to add her to their team. Some may opt to weaken the Pokemon using False Swipe and then repeat the above steps to trigger another encounter. It's arguably a lot better to use Hypnosis to put her to sleep or Mean Look to prevent her from fleeing though, both of which can be learned by the Gastly evolutionary line.
Another strategy involves tossing a Quick Ball straight away and then reloading the moment that Cresselia breaks free. It's not exactly quick, but it is definitely effective, particularly if players weaken the Pokemon first and then use this method on their second encounter with Cresselia. Alternatively, those with little patience may just want to use their Master Ball, as, given the mechanics in play, it could certainly be argued that, together with Mesprit, Cresselia is the hardest Pokemon to catch in Brilliant Diamond & Shining Pearl and thus warrants the use of such a rare item.
One Pokemon Brilliant Diamond and Shining Pearl player shares a video revealing what happens when a Ditto uses Transform on a shiny Ditto.