Capturing Mewtwo
Mewtwo is a Psychic-type Legendary Pokemon introduced in Generation I that is unlocked after adding a Secret Slab to your item inventory. It can be recruited on the fifth floor of Deep Aegis Cave or the sixth floor of the Dark Crater after being weakened by Bug, Ghost or Dark-type attacks, such as Scizor. Mewtwo can learn Psystrike, Shadow Ball and Aura Sphere, making it a valuable asset to your Pokemon team.
Capturing Lugia
Lugia, a Flying Psychic-type Legendary Pokemon who can learn Aeroblast, can be found on the 18th floor of the Surrounded Sea after Wigglytuff Guild member Sunflora talks to you about the dungeon̵7;s secret treasure. With a Secret Slab in your item bag, walk around until you enter a random battle with Lugia. It is weak to Rock, Ghost, Electric, Ice and Dark-type moves, but immune to Fighting, Grass and Psychic-type attacks.
Capturing Latios and Latias
Latios and Latias are Psychic Dragon-type Legendary Pokemon unlocked after a Secret Slab is added to your item inventory. Latios is found on the 24th floor of Midnight Forest, while Latias is on the 10th floor of the Spacial Rift. Neither Pokemon is affected by Ground-type move sets, but both can be weakened by attacking them with Bug, Ghost, Ice, Dragon and Dark-type attacks.
Capturing Darkrai
Darkrai, a Dark-type Legendary Pokemon and the only monster capable of learning ̶0;Dark Void,̶1; can be recruited in the Mystifying Forest after obtaining a Secret Slab. It is lurking in the 13th floor and will challenge you to a random battle. In order to weaken, him you will need to use Fighting or Bug-type attacks. If you do not have any luck encountering Darkrai in the Mystifying Forest, search for it in Lower Crevice Cave.