"Oh! Well, um, it's complicated." Connie furrows her brow, trying to think of a way to explain fusion that wouldn't involve digressions into explanations of context that would at least last ten minutes. "The best way I can describe it is that a certain alien species, the Gems, in my world has the ability to, um, fuse their souls and bodies to create a significantly more powerful being. Now, um, Steven, since he's half-Gem, can fuse with humans like me. When we're together like that, we're, heh, well, greater than the sum of our parts. Faster, stronger, more skilled, durable, the works. If things get dicey--like, say, surviving on a hostile alien planet for an indeterminate amount of time--we stay fused longer. That's what I meant when I said about only kinda having practice with sword and shield combat, since Steven's a shield specialist and I'm a sword specialist, our Fusion, Stevonnie, can use both."