I Am Not A Number
Everyone on this list is a number.
OK, maybe that's not quite true. Being designated as a number is considered to be quite dehumanizing, the resulting lack of empathy of those designated as numbers leading to some quite dire atrocities in our collective history. Generally, people with numbers for names are in the search for their original identities or are eager to escape the oppressive bureaucracy that has named them such. Sometimes they're just robots though. Really, either's a cool starting point for a sci-fi-themed game.