This Celestial Chain gives the user power over the physical planet. Not that they can literally rule the world, but that's what they do. The holder of this chain has control of the ground, earthquakes, and the like. They can open up pits, raise the floor beneath one's feet, and even shape mountains. This chain also gives the user a sword. Imagine that. To be at one with the earth, one must be at one with their mind. And what better way to do it than clearing the mind for swordwork?
Other than the random sword, this chain has some other abilities, but we're not gonna go into that (right now, anyway).