Well, following the maxim that a little knowledge is a dangerous thing, this would appear to be a factionless warlock or seer of some kind with a retinue of equally disparate assorted Eldar.
The leader. Impassive in his (her ?) wraith helm. Looking stern with a witchblade.
There are two swordsmen/women with convential weapons and two swordsmen/women with chainblades.
This individual is possibly the pilot of their grav-tank.
Two more individuals with hafted weapons.
So these are people who at the climax of the final battle for Xyphonica, when it looked like the Imperial Guard were over extended, appeared at XVII Korps HQ and negotiated.
