I won't give away too much of this because it is explained in the third book, but suffice it to say Tradis is the baby of the trio.
2. No Light Takes Place in the Early 2020's
While No Light actually takes place in the near future, the city is stuck in the 1980's as far as technology is concerned. The city's status as being the black sheep of the world means it has been mostly shunned. As a result, most of the city is run-down. The Corridor's technology is the polar opposite and another reason why the citizens of Ameritat resent the Dems.
3. The Containment Technology in The Corridor was Based off Motlin's Design
While the actual work was completed by Motlin's engineering mentor, the idea for the technology came from Motlin. That is how he knew the tech was built to eventually fail. He designed the prototype and could see the weaknesses.
4. Sarah and Rissa are Distant Cousins (very distant)
While the family tree split a LONG time ago, not all of the family was taken to Sinmer. Several members of the family escaped capture and stayed on Earth.
5. Sinmer is the Name of the Planet and the Only City
Sinmer is the only city on the only continent. It was built to hold just over 100,000 people and is designed in a square with the palace at the center.
6. Motlin's Marked is a Marine
After the land for the base was given to the Dems, the world sent (and continued to send) human military units to Ameritat as a sign of goodwill. About 300 years later, one of the U.S. Marines stationed there was Adela Ramirez. She was a sergeant at the time of her marking.