Yikes. Didn’t know super-villains were out here posting on Stack Overflow communities. Now, I want to get this out of the way right off the bat: in no way, shape, or form do I condone burning down an entire city and leaving no evidence for the next 4,000 years. Here at Water Cooler Sports, we pride ourselves on being pro-civilization and anti-arson. That being said, someone asked the question and it is my professional duty to answer it so we’re going to go OJ Simpson style (always the right move) and do the “If I Did It” route.
Plain and simple, you need a really hot fire. I’m talking like hundreds of thousands of degrees (I didn’t Google anything about the rate certain materials burn so that could be wildly high or it could be wildly low). In a modern day city, you’re going to have steel, iron, ceramics, plastics, stone, and (of course) wood. You can’t just light a match and expect the entire city to go up. So first things first, you gotta get yourself a scorned Maester to cook you up some wildfire.
Next up you need a proper distribution system. Even though you now have your mythical fire gel, you can’t just throw it on a building and hope the entire city goes down with it. No, you’ll need some way to blanket every square inch of the city with this stuff and what is the easiest way to have liquid cover an entire city? That’s right, rain. However, you only want to target this one city but trying to get your wildfire into the clouds is going to wreck havoc on so many other cities! No worries, you just need to either find Storm (of X-Men fame) or learn how to manipulate the Mutant X gene enough to inject it into yourself so that you can control the weather in a certain area.
Alright so now that we have a hot burning substance and a way to coat the entire city in it, all that is left is to make sure you are out of the blast zone. I don’t want to get into thermodynamics here (mostly because its been about 12 years since my last formal lesson on the subject) but when you ignite a fire, it gives off an immense amount of energy so even if you’re flying over the city and drop a match, you’re going to be fucked. The only safe solution is teleportation. You poof right above the city, drop a match, and poof out. Wham, bam, thank you ma’am the city is up in flames, every material known to man is being incinerated by the wildfire and you are safe on the beaches of Acapulco for the next 4,000 years sipping umbrella drinks, which is totally fine because the straight stuff sometimes hurts your throat. You’re not a pussy, you just want to enjoy the drink dammit.