They are going to be human. The worlds were colonized from a single spot: Hain. Even with differences, on all inhabited planets we will find human traits — from great civilizations to isolated tribes.

 

And the Ekumen is the one responsible for the alliance between each of these systems. A link among the worlds.

 

Ekumen is not an empire, far from it. It's a coordinator, not a governor. Its power comes from its countries and member planets, counting on almost a hundred of them. — For the expansion of knowledge, by increasing the complexity of intelligent lives, and trade interchange.

 

Profit in harmony. Without it, human interactions would be at random. And taking into account the immense distance between planets, this effort would be derisory without the Ekumen.