Pppphhhhhbbbbtttt… Under the cut, anon!
The Gems are a warrior species. Robots, even. They weren’t born, they were made. The kindergartens made this obvious. Think about it. If you made robots, you would need to give them an endless- or near endless- energy supply to keep them going. In the case of the Gems, it’s their gem. Who knows what is inside of their gems, but they obviously have something inside of the gems that needs to be protected and when their gems get cracked, they have to get it fixed or their internal hardware gets damaged and they fall apart.
What happened to the species that made them? We don’t know. Maybe they’re still around. Maybe humans made them, through extensive time travel. We really can’t be sure yet, and there’s so much more we don’t know, but there’s so much more to find out.
So, you have this warrior species or robots. The first couple hundred thousand or so are made on Homeworld, through small crystals. However, before the makers know it, there’s these practically indestructible robots coming at them, with a way to make their own weapons, and keep respawning, keep coming back. Oh, maker, what did you expect?
They overthrow their leaders, and start taking over worlds, because Homeworld doesn’t have the right resources after so many gems being made. Make more of themselves. Some planets though, they can’t support the machinery needed. Others don’t have the resources inside them, but they’re not totally worthless. Accommodations can be made.
Gems make classes. Leader gems, soldier gems, and servant gems. In these classes, there’s subclasses. You may have a soldier who’s a foot soldier, or a solider who’s made to command. Gems can be downvoted classes easily, but it’s hard to raise classes. Examples of these can be found in canon.
Pearl and Peridot are servant class gems. Peridot is meant to upkeep Kindergartens, and Pearl is a handmaiden. Amethyst, Ruby, Sapphire, and Jasper are soldier gems. Amethyst and the other mini gems are foot soldiers, their lives are expendable. Jasper, however, is a general. Maybe she started off as a low ranking leader, and lost ranks after her defeat, but who knows? Rose Quartz and Yellow Diamond are leader gems. Even if Rose is just a Quartz and not a Diamond, that would make her a lower level leading class.
Now, there’s more I could include here. Like my thoughts on things like how gem egg hell and tentadicks on gems fit into this, but really, this is long enough, don’t you think anon? Ask me later, and I can do those.