Castlevania Requiem: Symphony of the Night & Rondo of Blood was recently rated in South Korea, and it looks like things are starting to shape up a little more with an ESRB rating for PS4. [Thanks, @Wario64.]
No further information is known for now, but it shouldn’t be too long until we get some kind of announcement.
Castlevania: Rondo of Blood released earlier as a PC Engine title back in October 1993 in Japan. Its sequel, Castlevania: Symphony of the Night, released in 1997 for PlayStation.