From NoisyPixel:
For the first time in the series, you can control a ship in Ys X! Explore vast ocean areas using nautical charts as a guide, or challenge enemy ships in naval battles, adding a new element to the joy of adventure that is the true appeal of the series!
Battles have two modes. The first is the fast-paced Solo Mode allows you to fight alone with your partner’s automatic attacks and support being controlled by the AI, while the Combo Mode allows players to control BOTH characters at the same time to fight against powerful enemies. Furthermore, the Cross Action system allows players to fight in one of the two modes depending on the situation!
Our story takes place in a place known as the Gulf of Obelia, a northern archipelago with countless islands of all sizes.
Adol Christin encounters the Norman marine tribe and an undead tribe that assaults others known as the Griegers. Just what are they…
Finally, the site mentions a mechanic known as the Mana Action. Nothing much is said about it other than the fact that it “greatly expands your freedom in the open fields and dungeons.”