How many D&D warlocks would it take to blast a hole through the Pentagon?
In this wild world, you never know when information about the number of warlock lasers needed to destroy a government building will come in handy.
Warlocks are the best class in Dungeons & Dragons. In terms of storytelling, they have all the magical cachet of the other casting classes, but with the addition of a powerful and likely-mad patron—a free Non-Player Character to make story time with whenever the character or Dungeon Master chooses. They can make a coat out of flies. And they shoot laser beams out of their hands, long thought to be the pinnacle of human achievement.
How powerful are those lasers, though?
Eldritch Blast is a curious ability, sidestepping the use of spell slots by pretending to be a cantrip, but stepping up over time in lethal power. Flesh is weak, so if we're truly seeking a test of warlock powers then we need something more sturdy, like the United States Pentagon building.
Constructed during World War II in an attempt to confuse the Nazis with bold new shapes, the Pentagon has become so synonymous with the government of the United States of America that the location is now a metonym for the Department of Defense. It covers 116,000 square metres in the state of Virginia, and has been designed to allow the transit time between any two points inside to be 10 minutes or less. The walls are reinforced concrete, in addition to whatever secret construction the DoD's infinite budget allows.
Our warlock is the mighty Test, chosen by their patron at the age of 19 by promising extra university credit for participation in Warlock Test Program. Test is an aasimar, primarily for their Celestial Revelation, but we'll go into that more later. One of the only patrons that changes the damage or abilities of Eldritch Blast is the Hexblade; Hexblade's Curse allows the character to add their proficiency bonus to attacks against a target, but the target must be a creature, not a building. Instead, Test follows an Archfey patron, those tricksters being the most likely to request a big hole in the Pentagon. For now, they are a simple level-one adventurer.
To work out how much arcane force would be required to punch a hole in the US government, we first need to know how well a warlock would do against weaker buildings. A new, but modest, wooden residential building in a standard D&D 5th Edition universe has walls with an AC of 15 (as per the Objects section in the Dungeon Master's Guide). Test's hit modifier for elderitch blast is +5, meaning they have a roughly 55% chance to hit that AC, but for now we'll just assume they always hit. The wall HP is a little more nebulous under rules-as-written D&D, with the DMG stating that a large object that is fragile has 1d10 HP, and a very tough object would have five times that amount. This is a decent wooden wall, so we'll give it 20 HP.
Our warlock's blast does 1d10 damage, for an average of 5, although if we're factoring in the chance of a critical hit, it seems fair to bump that to a 7 to simulate the chance of multiple warlocks hitting the odd critical success. While a very lucky critical hit that rolls maximum damage twice could bust through the wall in one hit, the more likely outcome is a lot of damage the first round, and penetration on round two. When you consider that we want to punch through the entire shack, that at least doubles the walls and doubles the round estimate.
A level one warlock just isn't reliably powerful enough on his own.
If two warlocks are firing laser beams at the same spot simultaneously, however, that bumps it to a 14. Three warlocks increases it to 21, reliably destroying the wall. Six level one warlocks could punch through the entire wood house instantly, with enough zap left to kill the farmer's cow on the other side.
Let's move on to a stone building, like the one from the end of Monty Python and the Holy Grail. For the exterior shots of Castle Aaaaarrrrrrggghhh they used Castle Stalker, a rectangular fortress built around the 1400s in Scotland. We can safely assume that under normal circumstances a castle wall would be one of the most formidable structures an adventuring party might come across, so let's give it close to the maximum HP: 50. A map of Castle Stalker that I found online and was only available in German indicated that, at the centre, you would go through four major walls to get to the other side. That's 200 HP to obliterate. At 7 damage per hit, you would need 30 level one warlocks all casting Eldritch Blast simultaneously if you wanted a chance at blasting a hole right through the middle.
The Pentagon is significantly more structurally stable and complex than the castle from Monty Python.
As you can see from the map, the Pentagon is split into 'rings' which run around the central courtyard and split the interior into sections. These are labeled A to E. Each other rings functionally represents a building all of its own, with large walls on either side. There are also likely an untold number of walls inside the building, but for now we'll stick the basics. If we assume the walls are stone (concrete) and each has 50 HP, you're going to need a lot of warlocks.
143 warlocks, in fact. There are roughly 20 major wall structures if you draw a straight line from one side of the facility to the other, meaning the Pentagon's walls have 1,000 HP.
But, of course, that's assuming the Pentagon uses technology equal to a Scottish castle from the 15th century, which may or may not be true. When it was constructed, it was thought the Pentagon would become primarily a location for record storage, which means the architects and engineers built specifically with strength and structural redundancy in mind. Concrete buildings often use reinforced concrete, which is embedded with steel rods to increase the strength of the material. Additionally, unlike modern construction, which uses horizontally-spaced loops of steel, the Pentagon engineers used spiraling rebar. This means the walls of the Pentagon aren't just strong, they're unusually strong, even by today's standards.
D&D 5th Edition does not easily factor in the existence of steel-assisted construction techniques. If we assume the concrete is roughly equivalent to stone, then it seems fair and equal to give steel rebar twice the health of stone or concrete, 100 HP. Given that the evidence suggests the spiral rebar increases that strength even further, we can comfortably hypothesise that the HP of spiral rebar is even higher again, at perhaps 150 HP.
If each wall has spiral rebar supporting the existing concrete, the new per-wall HP becomes 200, and the total Pentagon HP in a straight line balloons to 4,000. It's possible the Pentagon also has ballistic sheeting and other protections in place, but this isn't the place for wild speculation. At 4,000 HP, that's 572 warlocks standing on the lawn, laser blasting. Even if you could find over 500 warlocks to do this job, the logistics of space and distance come into play. 572 people can't all stand and aim at one spot on the wall. We need way less warlocks. Also, the range of Eldritch Blast is 120 feet, and the Pentagon itself is around 500 feet wide.
For the first problem, we need to level up.
Taking our friend Test to level 11 increases the damage of Eldritch Blast to 3d10, a new average (plus critical) of 17. It also allows us to take the Agonising Blast invocation, which allows players to add a character's Charisma modifier to the Eldritch Blast, adding 5 to Test's attack for a total of 22. Test can also use Celestial Revelation's Necrotic Shroud to add their proficiency bonus of 4 to attacks on a target. Now their new average attack is an impressive 26.
Back at the Pentagon, we can surmise needing around 154 warlocks at 11th level, which is starting to look a little more manageable. At 17th level this drops to 117. Not ideal for accuracy, but impressive firepower.
Still, given that most campaigns end well before level 17, we'll stick with the realism of 154.
As for the distance issue, we can take a warlock invocation called Eldritch Spear, which increases the range of the blast to 300 feet. If half of the warlocks (77) run to the other side of the building and everyone eyeballs their shot for the Pentagon Subway Restaurant on level one, the tunnel should connect somewhere in the middle.
So, you need 154 11th level D&D 5th Edition warlocks to laser blast a hole through the Pentagon. As long as half of them attack from the other side. And just so you're aware, if you do have access to the contact information for 154 warlocks you should absolutely not attack the Pentagon. Warlocks have precious few healing abilities, very limited spell slots, and you won't have a single tank in the party capable of soaking rifle bullets. How much damage does a military-issue assault rifle do in D&D? Well, I'm glad you asked-