The acrid stench of tobacco smoke permeated my nostrils, nearly camouflaging the ozone-like scent of an impending timelike curve. Smoke was the second-worst part of the underground fighting profession. The first part was killing other nerds, but that was easier to acclimate to. The smoking gamblers would always underbet a girl, which meant more money for me. They were stupid, but that's why I was in the ring and they weren't.

Unlike the good-old-days of the twenty-first century, the gamblers and fighters here couldn't be more disparate. You don't stand a chance in time-battle unless you're brilliant. Out-think your opponent, and you win: your sequence of actions will murder them. Then go through the motions to complete the loop. You'll probably emerge unscathed, since you can always fake injuries after the fact.

On rare occasion, some muscle-bound punk with a normal IQ and fatal hubris will step in the ring. Those are a snap. Often, two steps of strategy are sufficient to squash them with your timeporter or annihilate them with one of your weapons. Overconfidence kills, so I always use ten at least. Plus, I had an unfair advantage. I was one of a dwindling handful of mathematicians in the world with the ability to intuitively understand [i]how[/i] time travel worked. I'd already terminated several of the others.

Battles were weird, but entertaining. Two contestants timeport in on opposite ends of a blastglass-enclosed stage. After emerging from your porter, you have ten seconds to size up the opposition and select three weapons. I usually take a toxic pistol and a concussion grenade for two. Some pistols are fakes. Others shoot bullets or shells. They all look identical from a distance so only the wielder knows. This is important, because the most common strategy is to make it look like [i]you've[/i] been killed. You try to cover as many contingencies as possible, so even if it looks like you're dead, you can go back in time and fake it to complete the loop, often with weapons you took off the guy you eliminated.

The real battle happens in the ninety seconds that follow. Two geniuses stare at each other and plan, like Jedi playing chess. After arriving, your porter is time-locked to the end of that ninety second period, which is when electronic betting stops and all hell breaks loose. You can't port in from outside the arena, because it's warded, but if you're clever you can still take action prior to the time limit. I like to go back in time and track my opponent down before the match and do something to weaken them without their knowledge.

This match was different. My timeporter didn't take me to the arena. It took me to a small room with two other timeporters, only one of which was functional, and that one took me here. I should have realized, but I didn't know I was in a mirror match until I saw myself emerge from the other porter. It was a clear setup by the Matchman, that incredibly wealthy fat guy with a facemask. He sat in the bleachers and ran the entire betting ring.

She was just as surprised as I, but asymmetry spread quickly. In mirror matches the curves aren't closed anymore, so literally anything can happen. This meant a significantly higher probability of double fatality. I grabbed a fake toxic pistol, a real one, and a fake concussion grenade (rubber shrapnel). My double selected a pistol, a concussion grenade, and a smoke grenade.

The thinking segment was excruciating. How do you outthink yourself? My twin keeled over onto the mat before the ninety seconds was up, which made it even worse. Did I poison her successfully? Was she faking? It seemed a naive strategy, but I wouldn't do something that dumb, would I? I tried to imagine every contingency, but I failed.

I never noticed that the timeporter that obliterated me was empty.

[hr]

It took twelve years to execute everyone else who might've had the ability to invent a time machine. I amassed a small fortune in the process. After finally hanging up the fat-man suit, I had to go back in time to invent the technology, but that was trivial.

My wife—the only other person on Earth who knew what I'd done—once asked me if it was hard to kill those two other versions of me. I replied that it wasn't hard, because the bitches deserved to die.

I hope she didn't take that response personally.