In response to the image, the voidwalkers weren't exactly riding them. The pigeons just sat at the edge of the map when I opened the ballista salvo corridor to let the voidwalkers in. It was a slaughter, and I only had a broken swordsdwarf nose to show for it.
How I can't wait for moddable siege engines... (WAY down the road).
Anyways, that pigeon thing is a side effect of giving them a trainable token (since they show up in very common biomes). Consider yourself lucky they didn't bring an animal that can actually kill you. Think of it as a (failed) test of the voidwalkers' new "homing pigeon defense array." Not all technologies work out in the end.
Also, I melted some masterful ethereal spheres I got from a Savant alchemist. He tantrumed, punched a brewer, and got lashed to death by the voidshard whip wielding fortress guard.
Has anyone gotten hadrine yet? I've gotten a few woven meshes, enough for 11 pieces of hadrine equipment. Should I make helmets or chestplates?
This problem seems to originate from the melt reaction (which is hardcoded). For some reason, melt reactions cause negative thoughts in the creators, but custom reactions do not - this was a major concern when I was testing slabs of accreditation, which turned out, thankfully, to be unfounded. I will probably introduce a special reaction to the smelter to specifically consume ethereal spheres and produce ethereal bars - this should give the same result without the tantrum effect since the object is "used" rather than "destroyed" by the internal definitions. This is something I can easily tack on to the next version.
And if your military is wearing anything less than d-steel, make helms. Helms save more lives. If you've got other high quality metals, though, chest plates have some excellent coverage. Putting both together is like creating a little mountain of metal that is only truly vulnerable at its extremities.
Also, in case you were wondering, it's impossible for me to create usable hadrine gloves due to the way DF handles left/right glove assignments (this cannot be replicated in a custom reaction right now). I could theoretically create boots and greaves, but they might come much later.