It shouldn’t be a spoiler to say that Alone Together delivered on its promise to enlighten us about fusions. Though if you haven’t seen the episode yet and have managed to avoid spoilers, we’re very impressed with you.
Not two people, or one
Stevonnie was the closest look we had ever gotten at a fusion. Opal and Sugilite, combined, didn’t manage as much screen time, and since Steven wasn’t a part of those fusions our perspective on them is much further out. All we knew was what they said and what others said about them: both seemed to imply that fusion Gems were their own entities, composed of but transcending the Gems that made them up.
There were always signs against this understanding: right in Giant Woman Amethyst and Pearl traded accusations about who was responsible for forgetting about the Geode Beetle of Heaven. In Coach Steven Pearl said that Amethyst and Garnet were losing themselves, and in Fusion Cuisine all three Gems retained the ability to argue with one another and control limbs independently.
Stevonnie’s introduction has made the discrepancies a bit easier to rationalize from a firm understanding: Steven and Connie both seemed to retain the ability to speak as themselves, but they handed control off seamlessly and without fighting—what Amethyst and Pearl were talking about when they mentioned who was responsible for what action of Opal. When two Gems are in-sync with one another, they can retain themselves while still composing something else.
There’s still speculation to do over the particulars, but now it looks like that the component Gems being subsumed into the whole takes time; Pearl was clearly concerned that the longer Sugilite was together the less Amethyst and Garnet would think of themselves as discrete entities. When Sugilite attacked Pearl, when the network polled Amethyst and Garnet for orders they may very well have forgotten that they weren’t just Sugilite’s left and right brains, so to speak.
The show continues to heavily imply that fusion is, for Gems, what happens between romantic partners where humans would instead have children. The dance between Garnet and Pearl especially seems to imply such a correlation, as does the way Steven and Connie effortlessly fuse during what would normally be a romantic experience.
That’s not to say that the Gems aren’t above harnessing such a thing for war. With fusion Gems apparently more powerful than their parts (it’s hard to imagine Amethyst and Pearl taking out the giant bird as themselves, and Garnet with her two gems is so much more powerful than Amethyst and Pearl it’s not even funny), it should be no surprise that there are numerous giant (fusion-sized, perhaps?) weapons on the battlefield in Serious Steven; fusions probably win battles, perhaps even wars.
If the Crystal Gems were training Steven in fusion to prepare him for a showdown with the homeworld, did Garnet want Steven’s first fusion experience to be a good one because his second one might be violent and painful?