Mana cores are what most species use to interact with mana. They gain the ability to manipulate that mystical energy to enhance physical prowess and create magic. That is why the humans implant a mana core in them since they are not born with one.
Human's mana core[]
For humans, the mana core must be placed at the nape in order to be transplanted, after which it will begin to flow into the cerebrospinal fluid. This process will bring extreme pain to the human. After the transplant, it is common to be bed-ridden for a week. One won't immediately gain access to mana once the transplant ends, humans need training, and body and mind have different methods.
Both organic and synthetic mana cores would need time to produce more energy once they became empty. They worked like normal organs. They required nutrients to refill the reserves of mana and allow their users to perform techniques again. A higher attunement would increase the maximum capacity, but it couldn't make it endless.
Synthetic mana core:[]
A Synthetic mana core is an artificial core created by the humans after observing the Nak's organic mana cores. Fastwite is one of the main composants in its creation.
The Synthetic core isn't a perfect recreation, though. Synthetic cores take longer to raise the users attunement with mana, and they eventually stop working as their fusion with the humans body is imperfect.
Synthetic cores last ten years at best when it comes to A-tier synthetic core.
Organic mana core:[]
An Organic mana core is mana core that comes from a species naturally doted of one. It usually comes from the Nak since it is a dormant organ within them, as they are very well attuned with mana. Organic cores are rare, and special training is required for the human body to accept them. Surgery with organic cores is risky, due to the fact that the fusion is tighter. This also means that replacement could lead to long-term injuries.
They have a thirty percent chance to leave long-lasting injuries during an upgrade. Those numbers worsened when it came to multiple transplants. A soldier who wanted to get the second upgrade of an organic core would have a fifty percent chance to remain severely injured.