(You look around and see several dead bodies scattered across the ground.)
(Judging from the equipment the corpses are holding, they appear to be grave robbers who wanted to steal the treasure of the Temple Vault.)
(You notice the corpse of what appears to be the leader of the grave robbers--his clothes are much nicer than the others, and he is holding a leather bag.)
(Inside the leather bag is a journal and a small toy that looks like a wheel.)
(Upon opening the journal, you see a map of famous treasure sites and items--some of them have an "X" beside them, including the Silver Blade Rotan.)
(The small wheel-like toy must be the object that can summon Rotan, so you put it in your cube.)
Find the Rotan-summoning item upon a dead grave robber.
There are dead grave robbers in front of the Stone Gate. Check if they are the owner of the Rotan-summoning device.
Several grave robber bodies were scattered in the passage to the Temple Vault. You obtained the Rotan Summoning Object from a body that looked to be the leader.