He's not normal

On the day Arthur and Nishizaka departed, the Noctem Dolls still lingered around the dungeon.

One of them, Norman, approached Ivaylo, who was still sitting and sewing his doll.

"What do you want, Norman?" asked Ivaylo.

"So, do you want to explain about Arthur? It seems too strange that you just let him go," Norman said.

"Ah yes, I also agree with Norman," Elinor continued. "Nishizaka's oath is very important because it can only work for one person. Plus, Nishizaka wouldn't want to kill Arthur. So what's the point of keeping him alive?"

"Maybe his eyes?" Adam interrupted. "That eye helps us a lot, even in the dungeon. Not only do its advanced detection capabilities allow us to perceive mana with great precision, but they also enable us to identify and decipher the various spirits that are present wherever we are. We can get a lot of information just by having that eye. Who knows what it can do when its level increases."