Many of you thought that the credits saying 'Cain Knightlord' were wrong. Guess what. They're not. Here's the thing:
Cain, Abel, Seth, and Lilith were created to be the leaders of the Mars colonies. Then, they gained the title of the "Night Lords". Thus, Cain, Abel, and Seth decided to base their last names off of that title. Abel chose Nightroad while Cain and Seth chose Knightlord.
These sort of things should really be explained in the anime.