However, whereas FFXII merged the turn-based action of the classic Japanese RPG into a new style of real-time combat, much as Bioware did when moving from Neverwinter Nights to Knights of the Old Republic, Revenant Wings is structured around a series of RTS battles. Vaan, his friends and his allies take the role of squad leaders or heroes, while espers play the part of the units you'd find in a traditional RTS. Through the use of crystals, espers can be summoned through gates built into the floor of each map. Send them or lead them into battle, capturing enemy summoning gates along the way, complete the map's objectives and you'll be rewarded with a cut scene and some new mission options on the main campaign map. While optional side-missions are introduced later on, things like side-quests and non-combat missions are notable for their absence. Revenant Wings is all about the strategy, you see.
Where the RPG elements do come in are in the equipment and career progression options. New arms and armour can be won in battle or bought with the spoils from a store on Vaan's airship (why Vaan's shipmates can't just give him the good stuff and wish him well is beyond me, but there you go). As the various heroes fight, they level up and become more powerful, and as the party grows in power, so does the ‘Affinity' of the characters - the property that allows them to summon and control more espers or more powerful espers. What's more, Revenant Wings also has its own version of FFXII's license board: a ring of pacts which enables our heroes to forge alliances with new and more dangerous espers as the game goes on, each unlocked esper opening up new options in the adjacent slots on the ring.
Cleverly, the various espers and heroes are already arranged in a basic Condorcet cycle, with melee troops vulnerable to flying troops who are vulnerable to ranged troops who are vulnerable to melee troops in turn. On top of this, espers have an elemental type that makes them more or less vulnerable to attacks of other types. It's a good system, because while it's simple enough to get your head around the different units - which is essential in a game that features over 50 different espers you can summon - there are enough combinations and new wrinkles to keep the combat interesting long-term.
Now, I always have my doubts about whether an RTS can work on the DS format, but Revenant Wings does a mostly excellent job. You can select units by tapping them with stylus, lassoing a selection or choosing the hero in command from a tab at the top of the touch-screen. The upper screen gives you an overhead map and unit-specific info when requested. Once selected, you can send the unit to a new position by scrolling the screen using the D-pad and tapping their destination with the stylus, or ask them to attack by tapping the enemy unit of your choice. Provided the battle is not too heated, it's not too hard to arrange your troops, keep up a steady flow of backup espers, attack enemy positions and defend against any counter-attacks.