Xenoblade Chronicles is a series of science fantasy real-time action JRPGs developed by Monolithsoft. Each game can stand on its own, but they all deal in similar themes and motifs, so if you like one it's worth trying them all out. (I would also recommend playing them in release order, i.e. 1 → X → 2 → 3, or at least 1 → 2 → 3, but technically you do not need to play one game to understand any of the rest.)
They are all individually at least 50 hours long just looking at the main story, and can easily approach 100 considering side content, so, yes, they will eat up a lot of your time. But also they are beautiful and extremely fun and have kickass music, so for me it's worth it. Maybe it will be for you, too!
Here is a brief description of each game if you'd like to get a feel for them!
On the bodies of two dead titans, the Bionis and the Mechonis, war rages between the organic life of the Bionis, the Homs, and the mechanical life of the Mechonis, the Mechon. When the Mechon attack his Colony, a young man named Shulk discovers that he can wield the Monado, a sword that can cut through Mechon armor and grants him the ability to see the future. He sets out on a revenge quest that escalates further than he could've imagined.
I have a shrine dedicated to Xenoblade 1 here!
The Definitive Edition, released in 2020, features an extra story called Future Connected that takes place in a previously unexplored area about a year after events of the main story.
In a world covered by a sea of clouds, humans live on living landmasses called Titans, who are steadily dying out. Rex is a young salvager who makes a living selling things he pulls up from beneath the Cloud Sea. On a job, he meets a mysterious girl in a sleeping pod named Pyra, who asks him to take her to Elysium—a mythical paradise no one but she and Rex seems to believe in.
This game has a DLC side story called Torna: the Golden Country, which acts as a prequel. You can play it after the main game is finished or after Chapter 7.
In the land of Aionios, two factions, Agnus and Keves, have been at war for as long as anyone can remember. But when a peaceminded Kevesi soldier named Noah, a determined Agnian soldier named Mio, and their friends are granted the strange power of Ouroboros by a man who belongs to neither nation, they become enemies of the world and are forced to question everything they know.
This game has a DLC side story called Future Redeemed, which also acts as a prequel, set 1000 years before the main story. I have a shrine dedicated to Future Redeemed here, but be warned: its basic premise spoils a lot of things about the main story of 3!
This game features a player-created avatar as the main character! You/your Cross wakes up as an amnesiac on the alien planet Mira. The last vestiges of humanity have crash-landed their spaceship there after escaping the destruction of Earth. You follow your savior, Elma, back to her Miran home, New Los Angeles, and join up with the rest of humanity to explore the planet.
The Definitive Edition, released in 2025, features an epilogue that picks up right after the events of the main story. It includes new locations and new characters.