Sony Computer Entertainment Europe just trademarked several titles from its PS2 catalog.
The list of trademarks include:
Dark Cloud
Rogue Galaxy
The Mark of Kri
War of the Monsters
Yesterday, a video published early leaked Dark Cloud as one of the PS2 titles coming to PlayStation 4 via PS2 emulation. These trademarks are likely some of the others.
A few other titles leaked before these, however, including Dark Cloud 2, Ape Escape 2, and Twisted Metal: Black.
On a more speculative note, Capcom recently trademarked Onimusha, also a PS2 title, leading many to believe a new title is in the works. But perhaps rather it is coming to PlayStation 4 as a PS2 emulation title?
http://gematsu.com/2015/12/sony-europe-trademarks-dark-cloud-rogue-galaxy-mark-kri-war-monsters#ET3FImRHK3zEZEfT.99
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