Trion Worlds posted a series of questions and answers today covering the upcoming 7th Legion DLC for Defiance.
The 7th Legion is an old organization that was founded shortly after the Arkfall, whereupon campers in the Yukon saw the devastation and decided to follow the bushido code of Yoshida Hiro. It's a faction that's different than others in the game, deeply embracing the cyberpunk western motif as it navigates relationships with humans and aliens alike.
If you want to learn more about the 7th Legion, give the Q&A a quick read! Players that purchase the DLC will be given a chance to enlist in the Legion and equipped with its signature gear and skills.