I got some details wrong, but it was still stupid. His character development was almost pointless in the end, since its not going to effect things anymore. He should have a choice of sacrificeing his freedom, but since JMS made the shadows allies all powerful on Centauri Prime (they literally are more powerful than the actual shadows at this point when it comes to controlling people) there wasn't one. Londo got defeated by bad writing. But, since JMS would go on to defeat Superman, Spider-Man and Wonder Woman with even worse writing, I guess Londo got off easy. Atleast Londo's "deal with the devil" didn't make him lose a wife, or cause him to take a very lame walking trip around Centauri Prime, or erase him from existence and bring him back dressed like a moron and with a new horrible backstory. Compared to what JMS would do later to some characters, Londo's horrible story arc almost seems just mediocre (I know the comic stuff is a bit different, but since thats how I knew JMS before B5, his comic book work is one of the things I think about when it comes to his writing in general).