Farplane
The Farplane is a one-room area (and pathway) that you visit while traveling through Guadosalam. Its purpose is to further develop the characters and the plot of the game.
The Farplane is an area that you briefly visit while in Guadosalam. Refer to the Guadosalam section of the strategy guide for more information:
Walkthrough Guide
Exploring the Guado homeworld, Maester Seymour’s mansion, and the Farplane.
You can pick up the 
Venus CrestMars Crest for Lulu’s Celestial Weapon, the 
Onion Knight. Travel back into the Farplane, and you will find a treasure chest on the left side of the screen. Open it to receive the Crest.
Note that this is where you’ll find the Venus CrestMars Crest in the 
PlayStation
Xbox
Nintendo Switch version of the game. In the Xbox and Nintendo Switch versionsIn the PlayStation version, this item is swapped for the Mars CrestVenus Crest. You can change the active version using the Game Version toggle in the sidebar menu. Refer to the Celestial Weapons section for a full breakdown of the differences.