There is no shop system in Oninaki like most RPGs where you are able to buy new weapons and such from in the game. Instead you need to find weapons and find Shadestones as loot which you can then use to Transmute. This How to Transmute for New Weapons and Shadestones will tell you everything you need to know about the process.
Transmuting is basically utilising other items you already have in your inventory in order to acquire a new item which more often than now will be a special item. In Oninaki you use the weapons your no longer want or use or sacrifice a decent weapon to transmute it into a more powerful weapon or even shadestones. To do this you must travel to Szaka on the World Map and select Deto and travel spot #2. Once at this location you need to go to the left and speak with the Alchemist, he is the same one that also deals with weapon upgrading and equipping Shadowstones.
After talking to the Alchemist select the 'Transmute' option, you will now be presented with three items to choose from. They will each have a number underneath them which indicates the power that is required to transmute into this item. After making your selection a list will appear on screen of all your weapons which you can then select from to transmute. You will be able to select up to eight weapons with the objective being to surpase the number it has underneath. When you achieve this the new weapon or Shadestone will be immediately created. There is also a possibility depending on the materials you used of getting a special bonus with the item. Once you have all three of the items you were presented with you can go and kill a certain amount of enemies as displayed on screen and return for a select of different weapons and Shadestones.
Check out our Shadestones Guide to find out everything you need to know about them.
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