Twenty

Fyndraxis had a tenuous, but passable grasp of nuclear physics. The color that his blade had been glowing had always bothered him a little bit. It wasn’t that it was an ugly shade of blue, in fact it was quite fetching in his opinion. It was that it reminded him of something, but he couldn’t quite place it. That something suddenly hit him like a ton of bricks. It was Cherenkov Radiation.
The edge of his blade was so irresponsibly, lethally, atom splittingly sharp, that it was honed to a single neutron. A neutron is indescribably small and with enough kinetic energy will make its way through just about any material. This includes atoms themselves. The neutron edge is connected to the rest of his sword. The sword itself has an almost infinite amount of kinetic energy compared to a neutron, or an atom for that matter. So in the act of merely swinging it through the air you are splitting atoms. Not a lot of them, but a statistically significant amount it turns out.
When atoms are split a couple of things happen. The atom splits in two, of course, but these two halves now have different amounts of protons and neutrons than they are used to. This changes these halves into different elements than they were before, because the amount of protons and neutrons that an atom has dictates what element it is. If you were to split an atom of oxygen, you might end up with a Carbon and a Helium, maybe some Lithium, who knows.
Also, an incredible amount of energy is released in the form of charged particles and high energy photons. Both of these will kill you, just in different ways. Both of these ways involve shredding your DNA to an unrecognizable soup of non coding base pairs. The blue light that Fyndraxis so proudly glows into the night are charged particles breaking the speed of light.
What you should be thinking right now is something to the effect of, “Bullshit, nothing goes faster than light, just ask that Einstein guy.” You would be correct in thinking this. The speed of light is the fastest thing in the universe and nothing can go faster than that. What most people fail to realize is that Physicists don’t really like doing difficult math problems, they make sure everything that they calculate happens in a vacuum to make the whole process easier. In a vacuum, you don’t have to worry about things like calculating atmospheric density. Mathematically, it makes a lot of sense, as almost everything in the universe is in fact in a vacuum.
Fyndraxis and the Sword he inhabits are not in a vacuum though. They are on Earth in an atmosphere of mostly Nitrogen, a decent amount of Oxygen and a touch too much carbon dioxide for everybody’s liking. When light hits a dense medium like the atmosphere it slows down. Don’t get me wrong, it is still moving unbelievably fast. The charged particles from a splitting atom have so much energy from the reaction that they are able to move faster than light can in the given medium. The resulting blue glow is a side effect of this phenomenon. It’s like a sonic boom, but for light. A Luminal Boom.
Fyndraxis liked to think of nuclear fission as a Grizzly Bear with minty fresh breath. Grizzly Bears are objectively an interesting thing to observe from a safe distance, but they have an ingrained instinct to maul you. You can observe them from a boat a half a kilometer from shore and feel pretty safe in the fact that you probably aren’t going to get mauled. Granted, Bears can swim, but you would see that one coming pretty far off.
If you make your way closer to get a better look, you start to push your luck and a mauling becomes more probable. When you venture close enough to be able to deduce the kind of toothpaste it would use in its morning routine, you will certainly be the owner of a brand new minty fresh corpse.