Doctor Layman looked towards Lucifer to see his expressions, but Lucifer seemed utterly expressionless. On the other hand, Caen had a smirk on his face as if he was enjoying it much more.

"Continue! Increase the pain index by twenty percent!" Lucifer commanded. There was not even an ounce of hesitation in his voice.

Doctor Rao kept screaming for ten minutes straight. His voice had turned hoarse, eyes were blood-shot red with tears still flowing down his cheeks, and his body trembled in pain. Everything seemed similar to what Lucifer had gone through.

Unfortunately, the pain didn't stop. It felt like, with time, it was becoming even more unbearable.

"Stop please!!!" he yelled like a lunatic as his bloodied eyes gazed at others in the lab.

"He can still speak. Not bad. I guess the pain is not enough. Increase by twenty percent. Take the pain index to fifty percent!" Lucifer said to Doctor Layman, who followed his commands without any question and increased the pain index.

Doctor Layman was surprised a bit at the commands, though. Lucifer was using almost similar words to the one that Doctor Rao had used. It seemed like he was mocking Doctor Rao now.

"Heartbeat slowing down rapidly. The pain index reached fifty percent. Cell destruction has reached 90 percent," Doctor Layman said.

He still remembered that Lucifer's cell destruction was only around seventy percent when his Pain Index was at ninety percent. But with Doctor Rao, it was much different. Lucifer was undoubtedly a more hard-hearted kid.

"Increase by fifty percent this time. Take the Pain Index to hundred percent," Lucifer said.

"We don't need to increase by fifty percent. He is at fifty percent pain index and ninety percent cell destruction. Only a ten percent increase is enough to kill him," Doctor Layman reminded Lucifer.

"I don't care. I want him to experience the same pain that I did. I want him to die at hundred percent pain! Do as I said!" Lucifer said firmly.

He didn't want the death of Doctor Rao; instead, he wanted the same death for him that he suffered, experiencing everything Lucifer did because of his actions.

Doctor Layman increased the pain index and turned it to the maximum as per the commands.

"Aaaah! Stop!"

Doctor Rao's body churned in pain as he felt as extreme pain as he possibly could. He was feeling like his body was going to blow up from inside out.

"Stoo-"

He made one last scream, but before he could even finish, his breathing stopped. Tears of blood could be seen on his cheeks.

As for his entire body, it was lying unmoving, looking pale as if all the blood had dried from his body.

His bloodied eyes were still open, but there was no focus on them anymore.

"Heartbeat has stopped. The pain index reached hundred percent. Cell destruction hundred percent," Doctor Layman announced.

"So, he died. He was a good testing subject to last for so long. I guess the human body is not as useless as I thought. If it can survive for so long under such pain, it's definitely anything but useless," Lucifer muttered as he looked at the data on the screen.

Even though he couldn't understand the data in the least, he was repeating what Doctor Rao had done.

What he didn't remember was that he was dead when Doctor Rao had said those words? Generally, he shouldn't have remembered those words in the end, but these words were still in his head for some reason.

"Master, what should I do with his body?" Doctor Layman asked Lucifer, who looked back at Caen in return.

"Did you see the buttons he was pressing?" Lucifer asked Caen as he walked over to Doctor Rao.

He removed all the wires and the headband that was attached to Doctor Rao before he caught the hand of Doctor Rao and pulled him off the bed, making him fall on the ground.

"Hahaha, yeah, I did. Go for it," Caen said, grinning.

He never expected he was going to enjoy it so much. At first, he was upset that he was stuck with a kid as a babysitter, but now he was actually starting to like the kid, and how his brain worked. He was also finding many similarities between them.

"Good." Lucifer nodded before he stepped closer to Doctor Layman, leaving the pale body of Doctor Rao behind.

Doctor Layman was wondering what Lucifer was asking, but he was hoping for the best.

"Master, did you like the work of your slave?" he asked Lucifer with a fawning look on his face.

Lucifer didn't reply and continued walking towards Doctor Layman, only stopping a meter away from him.

"Ma-" Doctor Layman once again opened his mouth to say something, but before he could even finish his first word, Lucifer fired two more lightning bolts, each at once of his hand just like he had done to Doctor Rao.

"Argh! Master! What are you doing! Stop!" Doctor Layman screamed in agony as his hands were destroyed. "I am your slave! Please don't!"

"I don't need slaves, especially not ones like you," Lucifer said to Doctor Layman before he fired two more lightning bolts at the legs of Doctor Layman before he carried him over to Doctor Rao's body.

Lucifer placed Doctor Layman's body on the bed and put the headband on his head before attaching all the wires like they were attached to Doctor Rao.

"No! No! No! Nonono! Please! Don't! I didn't do anything! Don't kill me like this! I can help you! I can help you a lot! I know many secrets! I can help you!" Doctor Layman yelled like crazy as he realized that he was going to be killed like Doctor Rao too.

"I don't care about your secrets. I don't care about you or about this world. Keep your secrets to yourself," Lucifer said as he looked down at the body of Doctor Rao that was lying on his feet, dead.