This is a hack

The newly hatched skeletons, who weren't skeletons, had some special properties.

They had excellent healing abilities and they weren't affected by the bugs' pheromones. More importantly- "Necromancy."

They could be turned to skeletons again. And this time, even Gob001 turned out to be a sentient skeleton. But it became a human skeleton, rather than a dwarfish goblin one.

This is a hack.

It really felt like a hack. I could make basically all my skeletons (even the ones who came out as husks) could be sentient. They could also be turned into humans.

But why humans?

Why not the original race?

Or did everything come from humans? But wouldn't that make the 'created by the primarchs' claim invalid? Or was this just the bug's or maybe my skill's limitation? Come to think of it, most of the humanoid skeletons look very much the same. So, there was a good chance this was partly because of my own skill and its limitation.