There's a mini comic showcasing their sibling rivalry.
Pirate Lord Blang was once a name feared across the galaxy, associated with power and cunning. As enigmatic as he was terrifying, Blang conquered planets and unified dozens of pirate clans under his banner. If his enemies resisted, he gave them his fury. If they served, he gave them his favour. In the end, he morphed what was once a chaotic assortment of thieves, deserters, and cut-throats into a controlled pirate empire.
At some point in his campaign, he met a woman. The details of this relationship are fuzzy at best, because he has since made sure to purge everything except for his private records. All that anyone knows now is that he's old, reflective, and has two grown twin children with no present mother. After years of half-hearted conquests, Blang has made it known that he wants to retire, leaving his empire to a worthy successor. When he appears now, he's always cloaked in shadow.
His twin children, Tennoc and Quaslan, both believe themselves to be the obvious choice, and each one tries to prove their worthiness over the other in a near constant battle for approval. As a result, the empire has unofficially split into two factions with leaders playing against themselves as much as each other. Each one has a part of what made Blang's campaigns so successful, but neither have proved worthy enough so far to have the whole package, and only their dad can ever smack any sense into them when they go overboard.
They regularly get into skirmishes with the Galactic Peace Keepers.