One of the antagonists in my story has won every battle he’s come across. Being a sort of “god” he is biologically and physically immortal. Meaning he can’t die of age and can’t die to inflicted injuries.
In most of this world, the population at large are currently at the medieval ages. If one gets close to him with the intent to harm, he’ll smash them to a pulp(literally) within a second. Since you wouldn’t want to be near him you’ll need a long range weapon.Of the weapons available at this time, there’s the longbow, the crossbow, and the rare musket. Of course, none of these weapons can actually harm him permanently.
His power basically goes like this: With magic, he can accelerate the rate at which his cells can reproduce to a mind boggling speed. Lopped off an arm? No worries; Just grew it back within 10 seconds. His DNA is essentially cancer proof even with his fast regeneration rate. The DNA strands cannot be “pushed off” their exact locations by normal means(am I describing this correctly, oncologists?). “Normal” being the amount of radiation usually found in the environment.
A group of knowledgeable people from Earth have come to this world. They too know how his regeneration works; so they’ve come up with a plan, they’re going to irradiate him so badly that he’ll turn into a living lump of cancer. They’re not sure about the method because there’s so many ways to do it! There’s Gamma-rays, X-rays, Dirty Bombs and so much more!(it’s kind of scary how excited they are for this)
Big problem though, what’s to stop him from turning into some Akira-type shit and consuming the entire planet?