While it was already known that a new VanillaWare and ATLUS collaboration was in the works, it has today been confirmed that the title in development is titled 13 Sentinels: Aegis Rim. The game is currently in development for the PlayStation 4 and PlayStation Vita, with no release date or launch window confirmed at this time.
Expect to hear more about this title in the coming weeks, but from what can be seen in the above minute-and-a-half announcement trailer, it at least carries across the visual style that I (at least) have come to expect from VanillaWare.
ATLUS USA have yet to comment on their plans to bring 13 Sentinels: Aegis Rim to market, but I would say an English localisation and release is almost certain given their past work with VanillaWare titles.