It's most likely just a Swordwind formation, hailing from Craftworld Biel Tan (who use a disproportionate number of Swordwind hosts relative to other craftworlds.)
A Swordwind (also roughly translated from the Eldar language as "leaves falling to cut") is an Eldar Warhost which features a disproportionate number of a Craftworld's Aspect Warrior shrines in its composition. Guardians are provided almost solely for vehicle crews, and the emphasis is placed on the embodiment of Khaine's aspects united. A Swordwind is often lead by a Craftworld's Avatar of Khaine, and is accompanied by The Court of the Young King-- a group of Exarchs (and their squads, sometimes) which attend the inner sanctum in which the Avatar rests.