Xenoblade Chronicles 2

Alrest is a world composed of giant beasts, the Titans, who eternally roam a sea of clouds surrounding the World Tree. The people of this world live on the backs of the Titans alongside Blades, weaponized life forms who are awakened from crystals and bonded to their summoner until either dies. The protagonist of this game is a boy named Rex, who lives on the back of a Titan he calls Gramps and makes his living by salvaging ancient treasures that have sunk below the clouds. When a salvaging job goes awry, Rex finds himself bonded to Pyra, a legendary Blade called the Aegis. In return for saving his life, Rex promises Pyra to take her home to Elysium, a fabled promised land atop the World Tree. Not only does he want to honor Pyra's wishes, but Rex also hopes Elysium will provide a home to the people of Alrest as the Titans grow old and die. However, Pyra's power and place in Alrest's legends and history mean several factions hope to take control of her. Rex, Pyra, and their allies will have to face those who wish to steal her away, including a terrorist organization called Torna with particularly nefarious reasons for seeking the Aegis' power.