Warning: Contains spoilers for the Prison Planet story-arc.
When Femur hatched, Sternum regretted not sitting on his egg when it was first laid.
His new brother was small, misshapen, and weird. His voice was an annoying squall, and could reach incredible volumes.
Sternum hated him. When he was told he was going to be a big brother, he had hoped for a smaller version of himself, someone quiet and cunning, someone who liked to hide in corners and just watch, waiting for the right time to do anything.
But Femur wasn't like that at all. He was loud, had no sense of timing, and demanded things instead of asking nicely for them. He was bratty, obnoxious, and, as he grew older, really crass and disgusting: Sternum could count up to the twenties how many times his younger brother spoke about his sexual conquests (which mystified him; who would sleep with Femur? Certainly the entire female population wasn't blind as well as deaf?).
But as they grew older, Sternum noticed something in his brother that he had never seen before: a certain kind of charisma, a charm, that was obviously innate but that was also honed into a finely-edged weapon. Despite his looks, his flaws, Femur was still able to draw people to him.
Which was an endless source of frustration for Sternum, who was desperate for comrades at his side, especially when he achieved his life-long ambition of stealing the throne. What Sternum lacked, Femur had in spades.
Still, Sternum was able to grab the throne without much help. And he was a good ruler, despite the circumstances, despite sometimes being a little too ruthless or cunning. He had thought he was making everyone happy.
What he had never counted on was that Femur, who had the charisma but not much else, also harbored that same lifelong dream. And when it came to the throne, blood was as thin as air.