We are looking at Parseman IV, a nondescript Imperial world with some agriculture and some industry, dutifully paying its tithes and generally, uneventfully bustling along.
But then, Caer Diomsach‘s farseers detected a huge disturbance unfolding, and decided to intercept this catastrophe at its root.
However, time and the warp are fickle things, and events did not go exactly to plan: a cult had formed and civil war was already raging on Parseman when the small Aeldari strike force arrived.
History tells us the following:
„The mission was to eliminate one nascent human psyker who would play a pivotal role in the history of Parseman, the whole subsector even, the outcome of which would bring untold grief to Eldar and humans alike.
Arriving at the eleventh hour, Fitheak Battleseer and her small force had to fight their way through the middle of an all out war zone to find this psyker, and when they did find what was left of him it was almost too late: He had already opened a gate for the armies of Chaos to enter Parseman in force.
Desperately, Fitheak took on the leader of the invading World Eater Blood Cult to deny them entry and get a chance to close the gate again, but obviously she had found her match in him: He was protected by his god from the powers she tried to use, and nothing she hurled at him seemed to be able to kill him. Grievously wounded, the battleseer went for a last ditch resort: Using her witchblade to cut off and bind that warrior’s essence with her own force into something, anything, and close the gate again, no matter the cost.
Her desperate attempt succeeded, she seized and imprisoned the soul of the Chaos Champion into the most receptable object at hand, her witchblade (which was, after all, made of almost the same substance as waystones), and sealed it with her own force. The gate collapsed. Caught on the wrong side of the gate and separated from the waystone on her armour, Fitheak’s soul frantically sought a place to hide from the predators of the Warp, and her best bet was, again, her witchblade.
The crashing warp gate shattered the sword, the blade went dull and was flung through the dimensions to end up more than a sector away, while on Parseman IV her soul-less, dying body was hurled into a ruined building by the implosion of the gate.“
Fayak Battleseer and her escort 
World Eater Champion and Berzerkers pouring out of the warp rift 
Eldar strike team closing in on the warp rift 
Fayak storming ahead to take on the khornite champion 
View form the warp 
While the Berzerkers charge the Eldar warriors, Battleseer Fayak engages their leader in single combat 
Berzerkers and Eldar at each other’s throats 
Hit for Hit, Wound for Wound, the leaders are trading blows 
Plasmaweapon and brute force vs. witchblade and psy powers, both are already severely wounded, with only Khorne’s favour and sheer willpower keeping them alive 
Finally Fayak manages to force the Khornite back through the portal and slays the Champion right inside the rift. It implodes, sucking her blade into the void… 
…and scattering her body. 
Imperial Loyalist troops survey the scene of battle, finding Fayaks Body as well as the mortal remains of the renegade Astartes.