A warp portal had opened on the planet of Seraphim Secundus and began spewing out daemonic filth of all sorts. It even attracted the interest of an sizeable Eldar force and an ork Warband. The imperials were quick to respond and try and close the portal sending Imperial Knights, Grey Knights, Space Marines, Space Wolves, and even the Officio Assasinorum. Both sides met in a titanic clash with forces arrayed not seen on Seraphim Secundus, probably ever.
Imperial Knights fell to Eldar ranged weaponry and the close combat of crazed Ork Tankhuntas. Culexus Assassins slayed Greater Unclean Ones. Daemon Princes hyped up on Mountain Dew were cracking Dreadnoughts and Terminators open and consuming the gooey center. Kugath Plaguefather himself was stymied by a Contemptor Dreadnought, but managed to destroy an Iron Priest. Soul Grinders were immobilized by intercepting Vengeance Weapon Batteries. In a sad tale, the Obsidian Knight 6 Stomped a Land Raider full of Kharn the Betrayer and Khorne Bezerkers. Kharn and the Bezerkers charged the Knight and Kharn bellowed a fell challenge to the Knight. Kharn was able to gain the initiative and destroy the Knight almost twice over before the Knight was able to raise a Chainsword. However the fates were unkind as Kharn ascended to Daemonhood to join his gene-father at his side.
Remembrancers managed to capture some images that can be found here.