A new Soul Sacrifice was announced called Soul Sacrifice Delta at Sony's Pre-TGS press conference. Soul Sacrifice Delta is a standalone game that will be purchased separately from the original Soul Sacrifice game. The Soul Sacrifice creator, Keiji Inafune, stressed that the game has lots of new features and content.
Soul Sacrifice: Delta features tons of new monsters, spells, raiments, maps, and more. The most notable new feature is the addition of a neutral force, in addition to the current chaos and divine forces. There will also be an option to transfer your save from the first Soul Sacrifice if you'd like.
For now the game is only announced to release in Japan in 2014, however a western release short after is almost certain. Its also important to note Inafune stated that after Soul Sacrifice: Delta is released, they will be releasing a brand new Soul Sacrifice game within a year after, presumably Soul Sacrifice 2.
The reveal trailer is below if you are interested in seeing it. Feel free to discuss what you think about the new game here.
Soul Sacrifice Delta Gameplay - TGS 2013