Every Tales game comes with new innovation to the battle system and Tales of Xillia is no exception. One of the latest additions to the battle system is Resonance Arte, which is somewhat of a combination of two skills into one.
Similar to the Tales of Symphonia’s Unison Attacks, Resonance Arte is a combination of two skills, resulting into a single, more powerful attack. For example, Jude’s Demon First attack, combined with Milia’s Wind Lance, produces Severing Wind Blade; a combination of both attacks. People who had played Tales of Symphonia would find this system somewhat similar, except they could pull it off every time without the required Unison bar.
For those who haven’t played Tales of Symphonia yet, Tales of the Abyss might provide a good reference using those Fonics Fields. Using skills in specific elemental fields, one could conjure up different skills, much like how Resonance Artes are like.
Resonance Artes extends towards all the characters apparently, with Milia’s spells combining up with both Jude’s and Alvin’s attacks. We can be sure to see more of these Resonance Artes when more characters comes out!