the most important part of having a magical fantasy land is of course the magic.
in this world, magic is produced by all living things as part of their metabolism, and is vital to life. without magic a creature will swiftly die, their body consuming itself in order to restore it.
This is a major danger in any workings of a spell, so any mage learns to recognize the symptoms of low magic and immediately cease casting
magic is split up into different disciplines a person can learn, though they arent mutually exclusive and anyone can learn any or all of them given enough time effort and of course money
magic can do most of the things a typical fantasy world can, but with a few exceptions: you cant create something out of nothing (the conversion rate of say heat into magic is very high but it still has to come from somewhere), you cant raise the dead, be it fully reviving someone or creating undead its still impossible, and you cant alter time.
pulling magic from other creatures is possible, but the creature must be either dying or ill from certain diseases that can weaken your connection to your magic
this is not seen as an inherently evil act, and can even be necessary for some spell, though doing it to another sapient creature is murder and so frowned upon
there are two main types of casting spells that everything else is divided between, quick casting (spells that take under 5 minutes to perform) and ritual casting (anything 30 minutes or over) (most spells dont take more than 5 minutes and less than 30)
of the two ritual magic can be far more powerful, as you can build up and store magic over time, resulting in an extremely powerful spell when its released. it is also the only way to make permanent effects on things, and is used for many forms of magical crafting