The Corrupted Empress

Another possibility would be to have a Buccaneer use Backspin Blow > Barrage > Backspin Blow > Barrage..... on the summoned job instructors and keep them away from everyone else so they can focus on killing Cygnus Empress. It'd also be possible to have someone of another class shove them all into the corner, if you want the person to possibly survive it could be a Paladin. Though having one person be the sacrificial lamb, assuming the bosses would continue to attack the one character like most mobs do after they've died, is another possibility. For looting it'd be possible to have someone with a pet + some move with invincibility frames loot everything that's near the Job Instructors.

Though it's possible this wouldn't work out too well if the different status effects can still hit without needing to do damage.

If I'm not wrong when the empress summon her knights she goes to the background, and it seems that the real problem is that each instructor do a whole chunk of damage (saw Mihile doing 12k) plus summoning a whole bunch of his/her knights (each doing around 5k).
May I ask does she really summons more than on instructor at the same time and any instructor more than once in the whole battle?

Also, is this the only vid there is of this boss? Because if it is then the only problem we might have is the whole pot cooldown which I'm sure people would find a way thru it, since we now have tanks and a bunch of defensive and recovery skill.