Okay, so nevermind that it took me almost a year to understand how "b1a4" is pronounced "bi-la-sa", nevermind how awesome I think it is that their fanclub name is the "bilasa raptors" (so cool; dinosaur references ftw!).  How about I only NOW discovered that they are called b1a4 because of their FREAKING BLOOD TYPES?! b1a4, as in: 1 member with blood type B and 4 with blood type A.  The plot thickens, people.  They are way more of a complexly named group than I originally thought.