The magic system (called Elemancy) in the newest installment of the Final Fantasy franchise significantly changed - you can't cast spells whenever you like anymore, you have to first prepare them. In this chapter you will learn how the magic system in the game works, what are flasks and you will find some tips that will be useful at the beginning of your journey.
First things first, we need to discuss the most important thing - how magic in Final Fantasy XV works. Contrary to most of the previous (and especially the older ones) installments of the series, you won't be collecting items unlocking spells, nor you will gain any by leveling up your characters. Instead, spells must be created manually - you have to collect the necessary ingredients, use those materials to create a specific spell and finally "equip it" on a character. Only then you will be able to use it in combat.
The magic in the game is based entirely on three elements - Fire, Ice and Lightning. However, it doesn't mean that you will be limited to three types of spells throughout the game - the spells you create can be modified in dozens of ways, allowing you to, for instance, poison enemies, decrease their combat capabilities, stop them in time or even heal the character that is casting an offensive spell. You can read about the process of modifying spells, as well as the possible combinations in the latter part of this chapter.
However, to be able to create a spell, you first need to meet several conditions. You must have a sufficient amount of raw elements (you can read about that in the next chapter) and a free flask - the flask is a container where the spell is held after creating it. Each spell you create will have a specific power (potency), additional effects (provided that you add a catalyst into the mix) and the number of uses. The spell disappears once you use all of the charges - the flask will be then cleared and you will need to create another spell.
Flasks are, basically, containers for spells - spells in the game are used as "grenades' that can be thrown into an enemy and the flasks are the grenades. You select the ingredients and raw elements of the spell you want to create and one of the flasks is filled with your creation. Afterwards, you have to equip the flask on a character, allowing it to use the spell you created with Elemancy in combat.
The amount of flasks you have is limited - at the beginning of the game you will only have a single one, allowing you to have only a single spell at your disposal. Fortunately, the amount of flasks will be quickly growing with your progress in the game storyline. Additionally, a flask will be cleared once you have used all of the "charges" of a spell and you will be able to fill the flask again - flasks aren't used up in the process of spell creation, the amount you have won't decrease.
Note - you can clear a flask on your own when, for instance, you don't want the spell you've created or you simply need an empty container. You just need to select the flask you want clear and press the button shown on the screen - after accepting your choice the flask will be empty and it will be usable once again.