* cut to Rosary the White Sorceress blocking access to it and summoning golems to keep everyone out *
* while Yggdra Union song "Onward, Rosary!" plays *
Okay, so to unlock the Custom Boss Arena, you need to defeat Rosary? Fair enough. Also, I was thinking of making it so that when you defeat all Rose Gold (RG) bosses, you'll be able to fight their master, who can be found in a void in Central Megalitha that takes you to a bonus dungeon. In each dungeon are voids that allow you to fight each RG Boss, though you can only access them once you've beaten the game once.