According to Urianger, the elements of fire and wind must be restored simultaneously to successfully complete the cycle of rainfall and evaporation. Unfortunately for you, this equates to facing the combined might of a pair of raging primals. Images of the ferocious Ifrit and the maniacal Garuda are made flesh, and you steel yourself for battle.
The encounter begins with the party facing Garuda alone. The walls are fatal and must be avoided. She begins by casting Super Storm, dealing heavy raid-wide damage.
Garuda's first actual mechanic is Occluded Front. This spawns vortices around the arena, which will periodically cast linear area-of-effect spells. Any tether which crosses a vortex's area-of-effect magic will be cut by the tether, and reassigned to a random party member. This is frequently fatal, so party members must take care not to cut their tethers.
Garuda casts Wind Cutter, tethering to each of the DPS, and then casts Storm of Fury, launching large conal area-of-effect spells along each tether and a point-blank area-of-effect spell around Garuda herself. DPS must carefully not overlap their cones, while also not breaking their tethers. This can easily be accomplished by assigning each DPS to a corner of the room and having that DPS run just far enough to avoid the point-blank spell, while not crossing a vortex line.
Garuda casts Air Bump, targeting each of the tanks and healers with a circular area-of-effect spell which will inflict Knock Up and Magic Vulnerability Up, and then dealing damage in a circular area-of-effect at the same location. If the party member is knocked up, they will be unable to avoid the damage spell, which will kill them. In addition, Air Bump will kill anyone with Magic Vulnerability Up, so two Air Bump circle cannot be stacked. However, the Knock Up effect can be avoided if the target is stacked with someone who was not targeted for Air Bump. Therefore each tank and healer should be assigned to a DPS who will stack with them, away from any other pair, to avoid the knock up, and then both will move out of the way of the damage hit.
Garuda then casts Ferostorm, spawning two nails next to her hitbox, that she then shoots two conal area-of-effect spells through. To avoid being hit, the party must stand at an angle from the nails.
Garuda casts Downburst, a blue circular area-of-effect spell centered at the center of the platform, which instantly kills anyone hit by it and knocks back and deals damage to everyone else. Since the walls are fatal, the party must take care not to be knocked into them. She then casts Air Bump again, so each pair must end up in the same place after the knock back.
The next mechanic is Vacuum Slice. Garuda flies to the middle of the platform and draws a linear area-of-effect spell through the center of the platform, leaving a purple substance behind that will instantly kill any player that touches it. Thus Garuda divides the platform in two, before casting Storm of Fury and Occluded Front. The vortices that spawn, rather than casting linear spells, explode in a small circle, after being sucked in towards the Vacuum Slice by Suction. Suction also affects players, so DPS must be careful not to overlap cones or be pulled into the Vacuum Slice.