Because the shades healed him after they nearly killed him. That’s why he can feel when the shade gets hurt?
Skender frowned his stomach hurting, his heart clenching. Why did he have to relive this moment? This moment of torture, blood, helplessness, and perhaps loss. He felt a sour taste in his mouth and every time Rayven landed a punch on the shade's face, Skender felt it in his gut.
"Looks like my wife is not yet satisfied with my performance. Shall I give you another sample!?" he whispered in a more seductive voice as she stared at him like she was meeting him for the very first time.