^this (give marshal applause with all 8 pairs of arms.)
Also an obsidian sword just sounds like FUCK YEAH I WANT ONE!
I'll see if Mako is up to the challenge.
On the subjects of the metals they are made of, how about Tungsten fists or atleast alloys of it since it is a dense metal
Osmium fists. Densest stable element, so why not.
(Lightbulb) (Adds Osmium armour to Delta Skärare)
But it is expensive and rare, so you may not find enough.
True.
On the topic of iron: I agree with Hyperion's (I think) point about purity.
Sorry for the awful necro, but I may have three possible explanations for the "iron". Bear in mind this is all pure conjecture, but I wanted to throw in my two cents.
The first explanation is that it's simply rule of cool. However, this is not in any way logical, rational or reasonable, nor is it anything like what intelligent people would consider, so we should discard it immediately.
The other two explanations are:
I think there is a possible reason why Iron was chosen over steel for Gipsy's hull. (Probably wrong in a lot of areas but meh)
While steel is much stronger than iron, iron is more malleable and less stiff than steel.
If a Kaiju struck against Gipsy if she was made of steel, the plates would recieve too much stress and would eventually snap and reveal the insides.
On the other hand, if a Kaiju struck Gipsy if she was made of iron, the plates would bend under the impact without snapping and revealing the insides.
Also, if you were to repair Gipsy, the steel plates would need to be replaced and welded back, while iron only needs to be hammered back into shape.
Or maybe via the power of fuck logic magic
Alloy or Non pure Iron Armour=Paper Mache
Iron Armour=Plot Armour
Now that i think about it, Pure Iron being Plot material is more plausible since all the other Jaegers were made of alloys and non pure iron stuff and they all didn't seal the breach while a Pure Iron made Gipsy did.
Gipsy wasn't the only one whose hull was "pure". Crimson Typhoon was said to be pure titanium with no alloys.
Honestly, though, I'd say that Gipsy's success where other Jaegers failed had more to do with its armament, pilots, and unexpected appearance than with the material its armor was made of (or the fact that it happened to be the "main" Jaeger, if we want to go the narrative route).