Imlerith - commander of the Wild Hunt and a frequent guest in Geralt's nightmares - had been chasing Ciri for quite some time, striving to deliver her to his ruler, Eredin.
This powerful and brutal warrior had fought in the countless battles and campaigns for conquest waged by the Aen Elle in other worlds. He prized physical confrontation above all else, seeking out direct, bloody skirmishes where opponents pit their strength, agility and training against each other in a contest to the death.
Imlerith attacked Kaer Morhen along with the rest of the Hunt. There the keeps defenders witnessed heart-wrenching proof of this warriors dangerous might. Vesemir, who had spent most of his long life with a sword in his hand, heroically stood to fight this foe but, to everyone's great despair, was bested after a bloody and hard-fought confrontation and perished at this monsters hands.
Regardless of race or birth, most warriors share common desires and delights. Imlerith was no exception. Awallac'h informed Ciri that he was wont to wallow in corporeal pleasures and would take advantage of his stay in Our world to attend the Crones sabbath.