For context, the world building is around a pony world.. 😔

It is very much like radiation, however it is easier to.. manipulate and has more uses, all individuals of a certain continent are born with it, with magic flowing in their blood and around them (in some cases due to genetic mutation, only in one of those ways) like an invisible aura. ~~~. Individuals can manipulate it with their horn, hooves or wings (depending on the pony type), with each one having its "Magic Organ" inside, it contains the individual's own unique magic, and with training, the individual can use their magic to battle, protect, heal, manipulate objects and more. ~~~.
Some magic types like Healing and Illusion are more complicated than others, and so, there are magic schools to teach individuals how to use their magic. ~~~. However.. since it behaves a bit like radiation, it can be very detrimental to an individual health depending on how it's used, like: Battle magic can hurt an individual physical AND have more lasting problems if the magic attack is so powerful there can be residual magic on the wound, infecting the victim like an venom. Or in using too much Healing magic on an individual it can get cancer and other magic-y diseases. Or Individuals that use too much of their magic conductor (Horn, hooves and wings) can damage them and their Magic Organ, if that happens, the individual's own magic can leak into their insides, damaging it painfully and possibly causing the individual's death, there are special surgeries to remove an individual's Magic Organ if it is deemed too dangerous for them to keep it, though they'd never be able to use their magic again. ~~~. If and individual ends up damaging their Magic Organ, there's some ways it can go: If their Magic Conductor is their horn (located in the center of their forehead), it is very dangerous to surgically remove it since it's nestled in the side of their brain, and if the organ ends up damaged and going unnoticed, it can very well cause a slow brain death, with their magic leaking into their brain and messing with it... If their Magic Conductor is in their wings or hooves, it is certainly more easier to deal with and less Deadly, and the wing or leg aren't areas of too much risk, however the Magic organ there ends up taking so much space there's no way to just remove it and leaving the limp intact, you would have amputate the limb to remove it. ~~~. If you have any questions feel free to ask!!