And what he says is basically "go see the numbers in this other thread", and then just builds off of that thread. That other thread only has calculations based on aluminum's ultimate tensile strength. Which, I'm going to point out now, is inherently flawed. Tensile strength does not give you the amount of force needed to cut through the layers. Shear strength does, and for aluminum that's 0.6 times the UTS.
The "galaxy" thing came from a throwaway comment of "you'd have to do something like throw a freaking solar system at it in order to do any damage" which then escalated to "it could survive a galaxy getting thrown at it". Which then went to math about figuring out the speed needed to penetrate to Leviathan's core when throwing the equivalent assumed mass of the observable universe with a restricted impact area of 1cm2 , ending up with a result of about Mach 160 or one one-hundredth of a percent of the speed of light.
All of that has literally nothing to do about how much matter the Endbringers have or are made up of.
So I have no idea why Wildbow jumped from "throwing x amount of matter" to "digging through x amount of matter" in
while explicitly referencing that very thread unless he either a) didn't understand what was going on or b) skimmed when he was responding to the JLA versus argument and accidentally misinterpreted it.
So it shouldn't be "dig through" it should be "throw", with the added caveat of "at sufficient velocities probably approaching a full percent the speed of light", all calculated based on this UTS thing which I've pointed out is already incorrect for something like Armsmaster's special blade.
I hate things like bad WoG quotes.
I've already said how I interpret the Endbringers' existences both in this thread and over in the Zizster thread, which is effective overlay. The Focalpoint shard over there is a decent (simplified) explanation, with the Endbringers' bodies being composed of matter projected from multiple sources through a single concave lens-like point. So the closer to the core/dimensional lens you are, the denser the matter is, even to the point of being physics-breaking, just like light is less spread out (and thus equivalent areas are bright) the closer you are to a concave lens.
If I remember that WoG correctly, the statement was, paraphrased, "to damage the core you need to throw the equivalent of the solar system at it, but by then you've already dug through a spiral galaxy's worth of mass". The main point I took away from it is that the Wndbringer core is ridiculously fragile compared to the inner layers surrounding the core.