I have a theory on who (or what) BG9 is supposed to be. The thought occurred to me when I was looking at an earlier blog post by Marioman53 called "Stern Ritter Titles: What do they mean?". In that post, he gave possible titles for the epitaphs of every member of the Stern Ritters; one of BG9's proposed titles was 'The Knight'. Then something came to me: in chess, when a player moves a piece to another part of the board, they say things like 'Knight to b4'. The chess board is like a grid, using numbers vertically & letters horizontally. BG9 could possibly be named from a shogi board (the Japanese equivalent to chess) as there are up to 9 spaces horizontally & vertically (a chess board only has 8 spaces). On the B space, a bishop & rook are placed behind the player's 9 pawns on the C space. On the G space, the opposing player's 9 pawns are present. In addition, on the A space, there are two knights placed adjacent from two silver generals, two gold generals, and lastly the king (with two lances adjacent to the knights). This might mean that BG9, his abilities, and personality could be a reference to pieces on a shogi board, or to the game itself.