Board Thread:General Discussion/@comment-25539649-20150510212536/@comment-26812261-20150526170358

Sharayna wrote: MisterNexus wrote: Eh, I don't see why not. They're obviously the true antagonists. But we only know of one that exists...

Steven Universe is a show that likes to drop hints about major revelations before they're actually revealed proper, so it's fun to speculate on dialogue, background art, and what have you. If a villain mentions "Yellow Diamond", and her faction's emblem depicts a yellow triangle plus two others, then there's probably a reason for it.