RealStyle is a new company formed in January 2011 by former Koei President Kiyoshi Komatsu. He left the Dynasty Warriors developer back in 2007, way before the Tecmo Koei merger.
While RealStyle has not said anything about their project, job listings give a hint. The entertainment company (they make e-books and CG too) is hiring iPhone/Android programmers and social game planners. Perhaps, this is for a tri-Ace social game?