A while back, my Pathfinder (1st edition) group was discussing late-game possibilities. I, playing a monk, noted that at 16th level my fists counted as adamantine for the purposes of overcoming damage reduction – I could literally punch holes in mountains, given a bit of time. I was reconsidering this conversation today and I got to wondering – what is the most efficient human siege weapon we can create?
So here's the challenge: We are faced with a standard castle wall, 10 feet thick and made of stone (Per 3 feet of wall thickness: AC 2, hardness 8, 540 HP, Burst DC 50). We want to create a 20-foot-wide hole in the wall, in order to create a breach wide enough for soldiers to attack through. Since a wizard would have no trouble with this, we will be disallowing all spells and spell-like abilities (including those cast through an item). We'll also ignore any siege weapons, excluding the PC themself. Everything else is valid, as long as it is official/published – supernatural and exceptional abilities, feats, magic weapons, and so on. How can we accomplish this in as few combat rounds as possible?
Less than One Round*
*No worms required.
Why bother damaging the wall when you can simply explode through it?!
Premise: The Wall has a Break DC. We're going to do that instead.
This answer is being updated with me being reminded that Mythic Rules are a thing. Everything about my build below is still accurate, but now I will show you how 10 Tiers of Dual Path Mythic Champion/Guardian let you clear out more wall than a Disintegrate spell.
When charging, you can now attempt to mow down 60ft of 10x10 wall and have the movement to do so. The DC may be higher than quoted below, but with a Mythic Power pool of 23+ (Extra Mythic Power is worth it), you can easily spend away to make your check...
= +139 (+144 1/min) (+2d12D1+1 if you spend another Mythic Power with Potent and Lucky Surge)
There are 2 Mythic Points of buffs and either 4-5 or 6-7 points per round that you spend mowing down castle (depending on how your GM reads the cost of Juggernaut).
And you still get to attack once per round, probably doing ~100 damage, all while exploding shrapnel 3/round and terrifying everything that stands against you. Protip: You're not making the DC 40 Reflex Save vs your Shrapnel, so pick the Guardian ability Absorb Blow.
As little as eight rounds without Mythic.
For this section, I will, assume we can choose to act on one 5x5x5ft cube in a round, so 5ft of wall will have a Break DC around 80 (subject to GM decision).
Build and Gear:
*Titanic Armor's Enhancement bonus only applies once per minute. Use it on the first inner section to make a strong entrance.
Total : +77(+82 once per minute)
Chance to succeed on DC 80: 90% (100% once per minute)
Estimated rounds to completion: 9, using the 100% ability once.
It was brought up that this should be considered a 10x10x5 wall for the purposes of destruction, which would reduce the time to complete it to about 4-5 rounds.
Other notable things
Feats Build (10 - 5 VMC + 1 Human + 7 Fighter)