Update: Continuum Shift will be out in Japanese arcades this December.
BlazBlue: Calamity Trigger will be getting an expansion called BlazBlue: Continuum Shift, according to the newest issue of Japanese gaming magazine Famitsu. Continuum Shift will feature at least one new character (Tsubaki Yayoi), new stages, new moves and rebalanced controls, and an improved HUD.
Continuum Shift will be making an appearance at Japanese arcades soon, with the Xbox 360 and PS3 ports to follow later. You can view more information about the new game (plus screenshots of Tsubaki) in this GameSpot forum thread.
In typical Guilty Gear fashion, you can probably expect Continuum Shift to be one of the many revisions and updates that Arc System Works has in store for BlazBlue.
For those who have played the single-player story mode on the console version of Calamity Trigger, you will perfectly understand what the title Continuum Shift suggests. Expect more convoluted plot arcs and endless recursions to follow in the BlazBlue storyline.
Give us a PC port, dammit.