The Godhand is probably one of the easiest Celestial Weapons to obtain. Once you gain full control of the airship, go to the navigational controls and use the Input function to put in a password. You will need to input GODHAND, which will place a new area in Mushroom Rock Road on the list. Go here to access an area you couldn’t previously reach, where you will find a chest on the northern end that contains the Godhand weapon.
Fully powered up, the abilities for the Godhand are:
- Break Damage Limit
- Triple Overdrive
- Double AP
The Mercury Crest is very easy to find, and you might even pick it up during the main story. In Sanubia Desert, there is a large area with a bunch of sand pits, some of which contain Sandragoras. However, there is a sand pit on the western side, in a little alcove of sorts, that just has a chest in it and no enemy. This chest contains the Mercury Crest.
In order to acquire the Mercury Sigil, you will need to do a lengthy sidequest named, Village of the Cactuars. It does not matter whether you win or fail the little minigames with the Cactuars during this sidequest, as the chest with the Mercury Sigil in the previously blocked off area will always be the Sigil.