Long story short, Reykr is Myrkr's closest sibling. Their father is incredibly abusive, and Reykr would be the only one who'd constantly try to step in and protect her from him, hence his scars. When "Miki," as he calls her, finally decided to run, there was no question in Reykr's mind he'd go with her. He's fiercely overprotective of those rare few he does care for, doesn't trust ANYONE but is ironically super gullible with those he holds dear (they can never do wrong in his eyes, pretty much), grumpy, sadistic toward those not in his circle, cynical, and can be very mean-spirited.