This is interesting. I've fought and defeated both the Ultima Weapon and the Emerald Weapon on disc 3, but the Ruby Weapon hasn't appeared in the desert around Gold Saucer. The man in Kalm is whining about the Desert Rose.
Maybe I shouldn't have defeated the Emerald Weapon before taking on the Ultima Weapon. Or maybe I should have killed the Ultima Weapon on disc 2.
Any suggestions?