Awhile back, I received a notification that former The Witcher 2 senior producer Tomasz (Tomek) Gop had updated his LinkedIn profile with a new executive producer position that he's taken at City Interactive since leaving CD Projekt RED back in June. Now, however, I see that he's added an interesting addendum: '"Project HUMAN". Unannounced Action-RPG for X360/PS3/PC. More details coming soon.' That leads credence to Gamikaze's report back in September that Tomasz had joined City Interactive to work on a new multi-platform action RPG with Deck13, which may or may not be the Blood Knights title that they're promoting on their homepage.
Beyond that, though, there isn't much information to dig up. About all we can glean about Blood Knights comes from the artwork on the placeholder website, which seems to suggest that vampirism will be involved, dual-wielding is a viable option, and that there just might be a cooperative multiplayer component. Hopefully we'll have more details to share soon.
UPDATE: Thanks to comments left by City Interactive's Tomasz Gop and Robert Malinowski, we now know that Deck13's Blood Knights is not Project HUMAN. In other words, there are two separate, newly revealed action RPGs to look forward to. Sorry for the confusion!