Recruit an ally to explore the streets, skylines, and undercity of Bulduq in Ys IX: Monstrum Nox together with co-op mode available now on Steam! Co-op mode can be played locally, or remotely via Remote Play Together on Steam! Check out the trailer to see how you and a friend can journey together and conquer the foes within the world of Ys IX: Monstrum Nox! Learn more about co-op mode h... more.