Kyurem resides in a massive structure composed entirely of ice known as the Glacier Palace, the existence of which was unknown prior to the events of Gates to Infinity. When the two protagonists and their companions travel to the mysterious Great Glacier in search of a fabled crystal that enable levitation, they enter the Glacier Palace and discover a corridor in which no one but the player is able to breathe. After all of the companions collapse, the room becomes dark, and Kyurem descends into the hall from a cloud of mist that hides the ceiling from view. He informs the player that he had foreseen their arrival, but the path before them cannot be trodden. The legendary Pokémon commands the travellers to leave but rewards them handsomely for their efforts.
The player encounters Kyurem again after he/she and his/her partner escape from Munna's thugs through the Scorching Desert. Hydreigon, the duo's current companion, assures them that deserts are naturally cold at night, so the sudden arrival of the ice dragon takes all three of the Pokémon by surprise. Without mercy, Kyurem proceeds to freeze Hydreigon solid and crush the resulting block of ice, thus destroying Hydreigon completely. With the lesser dragon out of the way, Kyurem then charges at the player and brutally stomps him/her into the dust, relenting only when the partner begs him to stop. Seeing that the partner Pokémon has lost the will to resist the future of destruction that the Bittercold (formerly known as the Great Crystal) ensures, he decides to have mercy on the player, believing that without the will to continue Hydreigon's mission, they will no longer threaten the fate that he has chosen to defend.
Kyurem explains his motives before he departs. He believes that the world has grown cold and wicked on account of the selfishness and distrust that pervades the hearts of Pokémon, and since the Bittercold is the very embodiment of these evil concepts, he has chosen to let the world reap its own reward: annihilation. Thus Kyurem defends the Bittercold, the instrument of the world's destruction, with every fiber of his being. Furthermore, he reveals that he believes the Bittercold will create a new, pure world once the wicked one is removed.
The Great Spire
Once the leading pair and their allies return to the Glacier Palace to destroy the Bittercold once and for all, Munna and her gang, who are revealed to be Kyurem's underlings, try and fail to strike them down. When the player and his/her partner complete the Great Spire and finally arrive at the room housing the Bittercold, Kyurem descends from the sky once again, ready to end their journey authentically this time. He comments on how weak the two of them alone are, claiming "In the face of so great a fate as this, you are like a soft breeze against a stone wall!" Believing the destiny ahead to be righteous and unalterable, he then attacks the two, beginning the main story's penultimate battle.
Kyurem's moves are Glaciate, DragonBreath, Slash, and Fly. These moves would ordinarily be no trouble to a veteran player, but Kyurem, being a massive dragon, is capable of hitting both heroes simultaneously with his attacks. Additionally, Kyurem is immune to most attacks while flying, and his Slash's high critical hit rate can make this a grueling battle for unprepared players.
Once Kyurem is bested, he falls to the ground. Although he still stands by the destruction at hand, he reveals that he would like to see what they are capable of. Kyurem then allows the two to continue into the Bittercold's lair, thus setting the stage for the final battle.
When the Bittercold finally falls, Kyurem saves the two by teleporting them away from the Glacier Palace, which is mere seconds away from falling to the ground. He expresses his gratitude for their bravery and commends them for having the conviction to save the world despite the opposition he posed. Deeply impressed by their valiant efforts, he teleports them and their friends back to their home next to Post Town.
Kyurem, in all of his forms, can be fought again by accepting a "Legend of the Mysterious Ruins" challenge request after completing the Worldcore dungeon. Kyurem reappears at a place known as Hoarfrost Tower. His alternate forms appear at another location called Turbulent Tor. However, unlike past games, these forms, or any legendary Pokėmon, cannot be obtained at all. The three exceptions are Virizion, Terrakion, and Cobalion.