Battle of Ka'mais
After the Maiden World of Lilarsus was destroyed by the newly-expanding Tau Empire in retaliation for a raid on Kel'shan, Craftworld Iyanden retaliated against the Tau by attacking the Sept of Ka'mais. Much of the planet was reduced to rubble during the reprisals, but the Tau held firm and launched well-coordinated counter-attacks after the initial shock wore off. The Tau even recovered several Wraithguards, the technology of which fascinated the comparatively primitive aliens. Due to Tau tenacity, the conflict continued for several weeks until both sides discovered that the initial raid on Kel'shan was done by the Dark Eldar Archon Andross Klax. Iyanden disengaged, snubbing the Tau's hand of friendship but nonetheless pledged themselves to making Klax pay for the unnecessary Eldar blood he spilled.