Phase 1:

Use your Garuda Egi. When the tank pulls set your Egi to Obey. Set down your Shadowflare on Garuda. Load her up with Raging Strike then at least 4 DoTs. Use Contagion. She'll Jump. Go behind the pillar. Use Aetherflow. Set down your Shadowflare on one pillar. When the feathers appear, DoT them with Bane. While the feathers die, load her up with DoTs. By the time you're done, the feathers will be dead. Reset Shadowflare on the tank. Before she jumps the second time, load her with DoTs and set Shadowflare on a Pillar and slightly in the middle. She'll Jump to the center and get hit by Shadowflare. Use bane when the feathers appear. Use Spur on your Egi.

She should jump a third time again to the middle and use scattered feathers. But at this point most of the pillars should be at or near full health. Load her with DoTs and use Contagion if it's up.

Phase 2:

The party should be moving into position for Aerial Blast. Set your Shadow Flare on the Main Tank. Use Contagion now if you haven't already. It will work no matter where Garuda is. Garuda will Call her sisters. "Obey" your Egi to Suparna and be sure Garuda's DoTs on Garuda should still be ticking thanks to contagion. The tank should taunt Chirada into Shadow Flare. Use Bane on Garuda to spread the DoTs to Chirada. Use Limit Break on them all. Chirada will also die in seconds after Suparna.

If you're the only SMN in the group, you'll move into Phase 3, just wash, rinse and Repeat. If more than one, you'll kill her before Phase 3.