Its own soul

When Zitra and Nero heard the Lich's words, their eyes widened. They put their full focus on the small rune that was forming in front of the Neo-Demon, and that already had more than one hundred thousand runic lines made. They could not hide the shock when they realized the incredible feat that Zatiel was performing.

Unlike the other two, Ezequiel and Tyrus did not show surprise. The Abomination Gorilla was confused since he did not understand how impressive a Soul Rune was. Tyrus' magic knowledge had grown over the years, but he never truly cared about things that did not directly help him to grow stronger.

The Supreme Neo-Demon, on the other hand, displayed calmness. For him, Zatiel creating a Soul Rune was not a reason for surprise. In his mind, he and his Master performing what others think impossible was normal.

When Ezequiel saw the confusion in the Abomination Gorilla, he shook his head lightly before speaking.