The characters in this instance are the starships. Unlike games like Space Empires, Reach for the Stars, or Master of Orion, you're not rampaging across the galaxy with massive fleets. In a typical game of Starships Unlimited, you might build only a half dozen ships. But each one is like a powerful playing piece whose capabilities are determined by the parts that you use to build it. Other games have taken this DIY starship approach, but none have de-emphasized the empire building aspects like Starships Unlimited.
Colonies are important, but they're rare because they're expensive to build and slow to grow.
But they're all streamlined so that you'll spend most of your time sending your ships on missions. One of the most surprising things about this game is how comprehensive it manages to be while still keeping the starships front and center. Your ships are similar to that game's heroes. The action moves quickly because it focuses on the exploits of a small handful of units. As they fight battles, they gain experience.