(Neo) G Red's Mirror Character, G Black, was an event-only borg distributed exclusively at the 2004 Jump Festa hosted by V-Jump magazine and through Capcom back when they were attending the Makuhari Messe convention center, and the only way to obtain it nowadays is through a hack or a bug.
Hacking the game also allows one to access the Galactic Emperor as a playable borg, as well as the combined borgs as a single unit. However, the latter borgs are barely playable and tend to freeze up during gameplay.
What Could Have Been: Mana's older◊ sister◊, Mina◊, whose role was cut from the plot. Significant in that she was going to be the primary antagonist; the position was instead filled by Orochi.
◊ sister
