The Hope of Ulthuan

A nigh-impenetrable Dark Elf fortification has been erected to the northwest. According to what you discovered in Tor Sethai, this is more than likely where Brathen and the other captives were taken. Brathen and the other military prisoners taken by the Dark Elves will likely face tortured interrogation at the hands of the Dark Elves. I have heard of such horrors before; victims are endlessly tormented until they give up their knowledge, then they are offered up to Khaine. It is said that such torment can last days, weeks, and by some accounts, even months. Go to the Dark Elf fortifications. Search for Brathen, and free as many of his fellow captives as you can.

Travel to the Dark Elf fortifications to the northwest. Free as many captives as you can. Afterwards, find Brathen Truseight.