|The new Pillars logo
UPDATE1: The game was spotted in Steam database under the name Nosgoth. It mentions Psyonix Comp and the app itself was added 4 months ago under codename: Black Cloth. Twenty days ago they changed the name to Nosgoth and logo was added. The profile it seems is being constantly updated. Interestingly enough, Psyonix had previously worked on a vampire themed game called Vampire Hunter: The Dark Prophecy, which was cancelled for unknown reason.
UPDATE2: Kevin Riepl (made music for Gears of War) states on his LinkedIn profile, that he was working on Nosgoth for Square Enix/Psyonix. You can see his portfolio also on IMDB.
UPDATE3: Kevin Riepl renamed the title "Nosgoth" to "Unannounced Title =) (VG) Square Enix/Psyonix", the same case as with the story board artist Richard Buxton earlier this year (he completely removed the picture and any reference to it).
UPDATE4: Nixxes, the company which ported all previous Legacy of Kain titles in the past, has posted two unnanounced titles on its page. Could one of them refer to War for Nosgoth?
I think as of this point of time we can deduce, that the game indeed exists and it might be announced very soon. In an article about Psyonix´ game, Gamasutra mentions their background:
"Founded in 2001, Psyonix is an independent game development studio focused on original IP creation and cross-platform Unreal Engine based productions. Located in San Diego, the studio has contributed to a number of blockbuster titles including XCOM: Enemy Unknown, Mass Effect 3, Bulletstorm, and Gears of War. Clients include EA, Epic Games, Microsoft, Sony, 2K Games, and Square Enix." (Cited from GamaSutra)
Psyonix specializes in using Unreal Engine, so this new Nosgoth game must use it as well. They only did one small title for PSN themselves, as they are more specialized in providing outsourcing for bigger developers such as Epic, Microsoft, 2K, etc. (Source: Psyonix official site).