How come this arcanist is invincible?

In a world where arcanists wield magic, the greatest advantage is their ability to create their own spells, unbound by the limitations of the magic network, and closer to the true essence of magic. However, their fragile bodies, slow growth, and vulnerability to close combat from warriors and assassins are significant drawbacks. What if an arcanist could transcend these limitations? Kane, a chosen sacrifice, awakens his immortality after a desperate transmigration, setting him on a journey to become a god. With his newfound invincibility, he embarks on a path to explore the true potential of magic and push the boundaries of what is thought possible.