Unfortunately, and likely due to the crash of the Exodar, the owlbeasts changed. Aberrant Owlbeasts, Deranged Owlbeasts, and Raving Owlbeasts attacked. They devoured Thalrisa and separated Cowlen from his daughter. He believed they were dead.
Under orders from Dulvi, some Draenei adventurers arrived on the island seeking Cowlen. He told them of his plight, and asked them to find the remains of his family amongst the Owlbeasts. The adventurers ventured into the island to do so. While they found remains, they also found Magwin. Offering their protection, they escorted her back to her father.
Though he was grateful for the ability to properly bury the remains, he was especially grateful for the safe return of his daughter, who he had presumed dead. He declared the Draenei his brothers, and offered Cowlen's Bracers of Kinship to them in thanks.
Later, as they were declared Heroes in Blood Watch, Cowlen traveled north to witness their ceremony.
Cowlen is a level 16 quest giver in World of Warcraft: The Burning Crusade.