In Star Ocean 5: Integrity and Faithlessness you can create almost anything with the right raw materials and a sufficient level. However, taking the creation system up a notch you can unlock the synthesis ability through the Happy Fun Bunny Time quest early in the game. The difference between normal item creation and synthesis is that you always know what you’re going to get when you use normal item creation. With synthesis you take anywhere from two to six items and the results can vary drastically with each and every synth.
There are a few ways you can narrow down the results of your synthesis. First off, you can determine the category of the result by selecting food, machine, medicine, metal, natural material or signeturgy under the Result area when starting your synth. You also have the type, qualities and impurities which tell you how well the items you’re using work together.
Type gives you the family of items the result of your synth will fall under. Quality has a maximum value of 50 and tells you the level of value the final product will have. Impurities also has a maximum value of 50 and informs you of how many imperfections there are that will limit your final product from being a legendary item.
Unfortunately, even if you manage to get quality and impurities to 50, your final item may still fall short. This is because there’s a range in which your item can fall depending on what you get for quality and impurities. The best you can do is get a value of 50, which still means the final item can have a value as low as 40. The value range will never be higher than the synthesis rating, and in most cases the range will drop between 10 and 15 points, with some exceptions.
In order to have a shot at the ultimate synths of each type, you will be quality and impurity ratings of 50, all the necessary items for the synth, and a little bit of luck. Thankfully there’s a save feature in Star Ocean 5 that can be somewhat abused when trying to get that perfect synth. Simply save your game just before you perform the synthesis, then see what you get as your result. If the result isn’t what you wanted, reload the game and try again.