The Hwo'kye Sept (i/ˈhwoʊ.kiː/; whoh-kee) was a long-standing Tau Sept that was completely devoured by Hive Fleet Erebus in 752.M41. During its participation in Operation Vral'y'he - a conflict between the Tau Empire and an offshoot fleet of an unidentified, entirely organic xenos species which would later be identified as the Tyranid race - roughly fifty Terran years prior to its fall, Hwo'kye made a move so bold and so swiftly devised that they unwittingly lit alight the circumstances that would birth their very own destruction.
Greatly confident in their own strength, and perhaps ignorant in the alien strength and adaptability of these xenos adversaries, the highest commanders of Hwo'kye devoted a wealth of Kor'vattra fleets to flank the approaching Tyranid spacecraft within several fractional solar units of the world the campaign was anchored to, accompanied by a planet bound ground force of almost nine hundred thousand Fire Warriors with associated crafts and weaponry. This force was combined with a sizeable deployment of Earth caste engineers assigned in the repair of weapons, battlesuits, and vehicles, and to assemble run'al and cadre fortifications.
Erebus however, after a phyrric Tau victory at this forlorn theatre of the operation, rejoined with a larger splinter of the hive fleet headed further toward the galactic northwest, speeding toward none other than the lushly populated Hwo'kye Sept, orbiting a star only four light years away from the sector of their grievous defeat. With a compromised Fire and Air Caste force having greatly been spent in reinforcing Operation Vral'y'he - amongst other operations -, the Sept was but futile in defending itself from the might of the Y'he.
Within less than half a single Tau'cyr, the sept was but wiped clean of all life, with only small reinforcing detachments of earth caste, a considerable fleet of water caste envoys, and whatever native Tau still stationed on Gai'kal being left free from destruction due to simply not being within the system at the time. The remaining population of Hwo'kye went on to become the seeding population for the newfounded Gai'kal Sept.