My pick is Future War Cult by use of the following process,
1. Dead Orbit reminds me of that game Dark Orbit which at its peak advertised on anything and everything internet related and emailed me constantly after I finally gave in and made an account and didn't enjoy the game. At all.
2. New Monarchy just, it seems like in just about every game with factions the people in favor of a monarch are always bad guys and I'm not a fan of bad guys.
3. Osiris, well I played a ton of Age of Mythology when I was younger so I hate Osiris. With a burning passion that can never be quenched.
4. Seven Seraphs makes me think of the P-Wing in Mario and I dunno, I can't take it as a serious group.
5. Future War Cult, well when I first saw it I thought it was a soccer team logo, and its got the most color and, I don't know I'm a pushover for red yellow and white