Injured?

"He's gotten stronger."

Blood Rain Demon Monarch nodded solemnly. "I can see that his protective sword technique contains an array formation. Although that array formation is still relatively young, after combining it with his own sword technique, its defensive ability has greatly increased. This Blood Sword Master has been trapped in my array formation for six hundred years. During these six hundred years, I didn't understand what he was doing, but now I understand!"

"He's using my array formation to perfect his sword arts. And now, he has already reached a certain level of success."

"Freak. In just a short six hundred years, and in a place like the Eternal Dark Prison, his sword arts have actually improved?" Thousand-edge Demon Monarch's gaze was frighteningly cold.