As dumb as the Teskans are, I'm surprised it wasn't the Filipods who conquered THEM.

Well it's important to remember that both species were still technologically, at the highest level, post gunpowder but pre-Bessemer and hydraulics at best. The Teskans have skin infused with sufficient extra Keratin to merit mention, which is like having a bullet proof vest built into your skin. One little known fact about bullet proof vests is that they are actually incredibly good at stopping not just old timey bullets, but also knives and swords, and even arrows. The Teskans are almost literally built to kill.

I was hoping this wasn't going to happen. The idea of the most bloodthirsty race in existence controlling the biggest weapon in existence is not one that thrills me. Especially since I am pretty confident that thing can survive the Tesskan learning process considering the fugitive ship that started all this survived a micro-meteor impact almost untouched, and still managed to auto land on earth. Honestly I think that thing just became a third side in the war.

Very true, but this does kind of excites me a little. Without knowing what is in the pipeline for the story, this wrinkle may be the catalyst that forces the Humans and the Makers to work together; especially if the Makers put all their eggs into one basket with the Spark of Thought.

And given the Makers' obvious arrogance in these matters, I would be unsurprised if that is what they in fact did.

"One little known fact about bullet proof vests is that they are actually incredibly good at stopping not just old timey bullets, but also knives and swords, and even arrows."

Not so much on the stabby, slashy armaments. A sufficiently pointy blade or worse, an ice pick or a stiletto (blade, not high heel shoe) will go right through a Kevlar fabric vest when punched in point first.

They are NOT "bullet proof". Hit something "bullet proof" enough times in the same spot and you'll put a hole in it. Same goes for bullet resistant glass. It's not at all like the movies and TV where bullets go sparking off. That's another movie stupidity, they don't make sparks. Either pyro is mounted on the thing being hit or the FX crew uses an airgun shooting plastic balls filled with spark powder. Bullet resistant glass breaks up while it's stopping the impacts. Fire a clip of ammo into an armored vehicle's windshield and the driver won't be able to see anything.

Kevlar is not shear resistant. In other words it cuts pretty much like any fabric, otherwise it would be near impossible to make bullet resistant vests from it.

Thin blades and other pointy objects (like sewing needles) spread the Kevlar strands and slip between. The sharp edges of a blade will also cut the strands.

Kevlar resists penetration by bullets because it has a very high tensile strength *and* high elongation before it will break. It also resists separation when the fibers are compressed sideways by *blunt* objects such as bullets.

Get into hand to hand combat with a perp holding a 6" icepick and your Kevlar won't do you much good at all. You'll have to rely on training to disarm the other guy before he stabs you.

The multiple layers in a Kevlar vest work together to spread out the impact of bullets and other objects. In many cases the outer layers will be penetrated by a bullet, especially types with pointed tips. As the bullet is slowed by the layers, it gets deformed and the force spreads sideways across more fibers, further resisting the impact.

Kevlar vests are somewhat helpful VS shrapnel because typical fragments are large with mostly blunt but rough edges. Even if they are moving at bullet speeds the impact will be spread over a large area. I've see a video on YouTube of a Humvee gunner who survived an IED hit without injury. His Kevlar had a large hunk of shrapnel embedded in the right side. It had come up from down low, cutting between the layers. He didn't know it was there until someone in another Humvee spotted it and pulled it out. (Which also meant the dumbarse wasn't properly inspecting his equipment!) Without the vest he'd have been dead or at least lost an arm.

A sufficiently fast moving bullet will make it through a Kevlar vest, which is why many of them have pockets over vital areas for hard plates. Those plates can be a variety of materials depending on the expected threat level.

The toughest plates can shrug off .50 BMG (half inch diameter Browning Machine Gun) bullets while barely being scratched, but they are expensive and heavy. Most of the plates allow a bullet to penetrate part-way then stop.

Kevlar vests weren't popular with Police until the first time an officer was shot while wearing one in 1979. The bullet was just caught by the edge of the front plate. Once word got out that the hot and heavy things actually worked, cops everywhere wanted them.

Yep, I remember when we first got the trial version of the improved Kevlar vests with the .50 BMG "chicken" plates in them (both front AND back). I was in the Rangers. Hot, heavy, but when one of our guys in Haiti in 1986 (disregard the "official" issue dates) took an RPG round to the chest which knocked him through a cinderblock wall (the RPG gunner popped up so close the rocket thankfully did not arm itself) and he not only lived, but was able to KIA the man who hit him, I became the truest of true believers. Beat the heck out of the old fashioned, Viet Nam flack vests or the first issue, front-only plate vests. Without the back plate the wall likely would have crushed his spine.