Ever since he was wounded, Nero hadn't tried to improve his strength. Not that he didn't want to, but he just couldn't. His meridians were majorly torn apart, his Spirit core cracked further, and not to talk about his divine sea. All these things were necessary to improve one's strength and he couldn't do that because of how they were at the moment. If he wanted to advance any further, he would have to at least heal them to some extent; hence, why he's about to knock on death's doors.
Nero took out a luminescent crystal and slowly walked into the dark cave while releasing his perception to cover over a dozen feet around him. It turned out that the cave entrance was many times smaller than the actual height and size of the cave. Nero's perception wasn't able to completely cover every angle of the cave; that was how big it was! And even with the help of the luminescent crystal, it was still difficult to maneuver his way through this cave.
