4Gamer recently published an article offering more details on some general combat mechanics and some character-specific tidbits within the battle system. Siliconera offers some translated help.
Once you approach close enough to a monster or a party of monster, the game will seamlessly transition into battle mode. It’s not immediately clear, but it’s possible that battles will take place within a bounded arena à la the modern Tales games – so there are seamless transitions like Xenoblade, but perhaps not with the ability to evade freely. You also have the option of issuing quick, general commands to your A.I. allies helping you in battle.
The 4Gamer article seems to promise unique attacks for each character and combo possibilities specific to certain pairs. It also speaks a little more regarding offensive mage types – they are called Dragners, who use their instruments to attack with various powers of nature. It seems Rinna most readily identifies with wind elemental powers while Agnam identifies with fire, but that isn’t to say more elements won’t be available in the future. Most surprisingly, it seems that there’s a certain risk to Irvan’s dragon form; apparently the risk of Irvan going berserk increases the longer he is in his dragon form!