Upon visiting the Abundant Shrine, the player will cross a group of three children arguing just before the shrine. They collectively tell the folktale of how "Great Landorus" allegedly punished two other Legendary Pokémon (Tornadus and Thundurus) for wreaking massive destruction across the land with their ferocious gales and fierce thunderstorms. As such, the thankful inhabitants of the land—saved from the danger posed by the Cyclone and Bolt Strike Pokémon—constructed a shrine in honor of Landorus.
In Black 2 and White 2, it is revealed that the Forces of Nature were in their Therian Formes in the time period depicted in the myth. A man suggests that he is unsure whether the Therian Formes or Incarnate Formes are the true Formes of the trio.
The player can encounter the Forces of Nature while soaring in the sky. TornadusOR/ThundurusAS can be encountered in the Stormy Clouds located near Fortree City if the player has a Castform in their party. Landorus can also be encountered in the Stormy Clouds located near Fortree City as long as both Tornadus and Thundurus are in the player's party.
Pokémon Ultra Sun and Ultra Moon
The player can encounter the Forces of Nature in the Ultra Space Wilds' Cliff World dimension by traveling through red warp holes in Ultra Warp Ride. Tornadus is exclusive to Ultra Sun, Thundurus is exclusive to Ultra Moon, and Landorus appears only if both Tornadus and Thundurus are in the player's party.
Once Landorus finally appeared, the three fought viciously, eventually becoming tired out. At that point, Team Rocket attacked, with Dr. Zager using a weapon on his helicopter to trap the three in laser boxes so they could be taken away. When Ash and the others attacked the helicopter he was forced to release them, and they went back to fighting until Lewis's Revival Herb gave Landorus the strength to subdue Tornadus and Thundurus. The Forces of Nature then used their respective powers to heal Milos Island before leaving for good.
The Forces of Nature in their Therian Formes in the anime
Tornadus, Thundurus and Landorus appeared again in Unova's Survival Crisis!, as the final goal of Team Rocket's Operation Tempest. In the episode, it is described that they together have the power to control nature, which can be harnessed by one who possesses both Meloetta and the Reveal Glass. Giovanni lead a massive charge of Team Rocket's forces in a bid to capture Meloetta, then took it to the Abyssal Ruins to acquire the Reveal Glass. Using the Reveal Glass, he summoned the Forces of Nature and transformed them into their Therian Formes, enslaving them to be his servants.
A great battle ensued, pitting the Therian Forme Forces of Nature under Giovanni's control against Ash, his friends, Ridley and Cynthia. However, after absorbing a Thunder attack from Thundurus, Ash's Pikachu used a gigantic Electro Ball that destroyed the pedestal atop the ruins, freeing Meloetta and causing Giovanni to accidentally look directly into the Reveal Glass. As a result of losing Meloetta, who acted as a medium for the use of the trio's power, the power possessed Giovanni and bent him on destroying all of Unova. After Giovanni was saved and Team Rocket fled a short time later, the Forces of Nature were calmed by Meloetta's singing and transformed back into their Incarnate Formes when Ridley used the Reveal Glass himself. They were last seen disappearing into a portal in the sky as the Abyssal Ruins returned to the depths of the ocean.
In the manga
Tornadus, Thundurus, and Landorus in their Therian Forme in Pokémon Adventures
In the Be the Best! Pokémon B+W manga
Only Tornadus appeared in the Be the Best! Pokémon B+W manga.
In Pokémon Adventures, Thundurus was the first of the Forces of Nature to appear. He appeared at Nimbasa City just after Black won his Gym Battle with Elesa. Tornadus was next to appear; he clashed with Thundurus at an open field where a railway line passes through. Shauntal and White witnessed the clash while on the Battle Subway; they also witnessed Landorus arriving to stop them from fighting.
They are based on kami in Japanese mythology: Fūjin, the kami of wind; Raijin, the kami of thunder; and Inari, the kami of fertility, respectively.
They may also be thought of as representing the different domains of world: Landorus represents the land, Tornadus the heavens, and Thundurus a transitional state between the two (lightning).
Each member of the trio bears features with strong resemblance to magatama. Some of the spots that cover their bodies are shaped like them, as are their tails: a bulbous head with a thinning offshoot, most prominent in Tornadus.
The concept of Incarnate and Therian Formes and the Reveal Glass may be based on ancient Chinese Yaoguai, animals/plants cultivating the universal powers for thousands of years to become deities, but their true identities can still be revealed by the Demon-Detecting Mirror.
Incarnation is the process of an immaterial being taking on a material form, with this material form being an incarnate. Therian refers to something with a spiritual or psychological association with an animal.