Earlier this month, Konami filed a trademark for the mark "Castlevania: Order of Ecclesia" with the USPTO. We presumed that this could either be a new DS or mobile Castlevania title, but given the resemblance in name to last year's mobile CV title, Order of Shadows, all bets were on mobile.
However, according to a new ESRB listing, Order of Ecclesia has been rated for none other than the Nintendo DS. While Konami has yet to comment on the existence of the title, we should hear more soon now that the secret is finally out.