This phase is quite similar to the story mode phase 1, with the addition of Mistral Shriek. Garuda should be tanked on the North side of the room where she starts. Pull her as close to the wall as possible so that Wicked Wheel does not hit the rocks in the center. The group should all loosely spread out on the left side of the room, careful not to be too close to the rocks. While it is ideal to be completely spread out, Friction hitting multiple players is not too damaging and will actually occur semi-frequently later on in the fight. The tank should make an effort to run through Garuda to dodge Slipstream, as it is quite damaging and stuns as well.
Garuda will vanish roughly every minute in the fight and use either Mistral Song or Mistral Shriek based on position. When either of these abilities are used, you need to make sure you break line-of-sight with Garuda using one of the rocks. Luckily, these will always follow the same pattern and will be easy to predict. On the first vanish, she will reappear on the North side of the room where she should be tanked already and use Mistral Song. A minute later, she will appear in the middle of the room and cast Mistral Shriek. Finally, on the 3rd vanish, she will appear on the East side of the room and cast Mistral Song again. While this can continue into another Mistral Shriek, your DPS is likely too low if you reach that point.
After each Mistral Song or Shriek, Garuda will emote "Countless feathers rain from the sky," summoning a large number of Razer Plumes directly below her. As a White Mage, I will activate Cleric Stance and Swiftcast during the Mistral abilities and use Holy roughly one second after the emote. This will usually stun nearly all the summoned plumes, making them easy to pick off. In addition to these plumes, when Garuda is nearing 50% health, she will shout "Soon you will see the depths of your folly, mortals!" followed by her vanishing and appearing in the middle. This summons plumes along the walls, rather than under her. Whenever plumes are spawned, they must be killed quickly to prevent them from destroying any rocks.
Shortly after the final set of plumes are killed, Garuda will once again appear in the middle and begin casting Aerial Blast. While you do not need to line-of-sight this ability, moving behind one of the rocks still makes a convenient stacking point to put down Sacred Soil and pre-cast Medica II/Succor. This will mark the end of Phase 1.
After Aerial Blast, the tank should shift from the North position into a North-West tanking position, while the ranged classes all stack on the wall directly to the West. You should end up in this arrangement. This will allow the Great Whirlwinds to appear harmlessly around everyone, as well as create a section for the adds to be tanked in. Shortly after the Whirlwinds appear, Garuda will vanish and appear on the south side of the room. In addition to Garuda, Suparna and Chirada will also spawn. These will use all the same abilities as Garuda and should not be faced into the group to avoid Slipstream stunning everyone.
When Garuda vanishes, everyone except the main tank should stack in the range pile, while the main tank should not move. Garuda will be running in from the south side and will Slipstream on her way in. This positioning will prevent anyone from being in front of her except for the tank. After avoiding slipstream, everyone will need to kill the add which is linked to Garuda with a green beam. DPS should use cooldowns to bring this first add down as quickly as possible. It will be quite difficult for the off-tank to establish aggro on this add, so whichever DPS ends up tanking it should move out of the group. If you only see a red beam, kill the opposite add first, as the beam does not always appear, but the buff it grants will still be on Garuda.
The off-tank should grab the add with the red beam and tank it facing away from the group at this position. The main tank can also pick this add up if you're only running with one tank. This will be the heaviest damage during the encounter. One healer should focus on keeping the main tank alive through Garuda's increased damage while the other focuses on the large amount of AoE healing needed from Friction and Wicked Wheel hitting so many players.
Once both adds are brought down, the Great Whirlwinds will start to fade. As soon as the northern whirlwind fades, the tank needs to run along the wall to the North-East side of the room. The whirlwinds will start to rotate, forcing the group to move clockwise around the room. During this time, a group of Razer Plumes and a single Satin Plume will spawn. DPS should kill the Satin Plume as quickly as possible to avoid the sleep debuff. The Razer Plumes are easy to heal through, so ignore them in favor of more DPS on Garuda. Once you reach the East side of the room, the whirlwinds will fade completely and everyone should move to the middle of the room to prepare for Eye of the Storm.
While in the middle of the room, Garuda will vanish again, reappearing in the South with Suparna and Chirada spawning on the East and West sides of the room. Each of these adds should be tanked on the edge they come in at, with the main tank on Garuda (South), the off-tank on the add with a red beam (East or West) and all the DPS on the green beam add (East or West). This leaves the healers either in the middle or on the North edge, free to heal up everyone.
Once the adds have been finished off and Eye of the Storm fades, all the ranged players should move directly South, with the tank should move to the South-West position. More Great Whirlwinds will spawn, which will start to rotate as more plumes spawn. Once again focus the Satin Plume down and ignore the rest. You will rotate around the room until you're roughly in the same position you started Phase 2 at. She will vanish, spawning one last set of adds. Use Meteor, the level 3 limit break, to nearly kill both of them instantly and finish off Garuda. If she is not almost dead at this point, either DPS is too low overall or the add with the green beam has not been killed quickly enough each time and healed Garuda too much.