Kartal was trained from a young age to hate humans. He'd been taught they'd taken Strix land, and that it was up to all the Strix to fight to get it back. As such, he was trained as a scout and assigned to a veteran group that had recently lost theirs.
The group was quickly thereafter assigned to raid a certain area near Varissia, and outfitted themselves for the long haul and took flight. The tree line was so thick the group had to land or risk missing the designated area altogether.
This would prove to be disastrous as the group was slowly hunted down to the last member, which as fortune would happen was Kartal. Finally, the creature that had killed so many came into view. While Kartal didn't know at the time what it was, the lizard like being knew what Kartal represented, dinner.
It stalked the boy slowly, relishing the fear coming from the boy, and enjoying its little game. This became it's downfall however as the chupacabra was set upon by Varisians led by two clerics, one of which was Harrow born. The Harrow born woman then called the warriors away from attacking Kartal as well, she'd done a Harrowing a few days previously, and the intrepretation had just come to her that she was to adopt the young Strix into the clan as his mother. Desna, it seemed, had plans for the young Strix.
Kartal slowly learned to overcome his hatred of humans, coming to see the Varisians as his new family. He knew he'd face hatred from humans not as open minded, but as he grew older, he felt the desire to wander as most Desna clerics do. Pledging himself to the ideals of the very luck that had saved his life, he left his mother. His mother as a parting gift left him with the very Harrow deck that had led her to him years ago.