Netherworld text?
Yue Jinghua realized she had overlooked a very important detail.
Now that she calmed down, she instead noticed this detail.
Earlier, she hadn't paid attention to the netherworld text on the bones of Emperor Demon Yuan, because she thought the netherworld text on Emperor Demon Yuan's remains was no different from that on the earlier Emperor Demon Coffins.
But on closer inspection, she found that the two were actually not the same.
The netherworld text on Emperor Demon Yuan's body seemed more like... a Divine Rune.
Yue Jinghua is a Tattoo Master, but she hadn't wielded her tattoo needle in a long time, seemingly since she inscribed the divine rune on the Compass.
The time was so long that she overlooked that what was on Emperor Demon Yuan's bones might indeed be a form of Divine Rune.
If it's a Divine Rune, there's a way to break it, at least Emperor Demon Yuan isn't truly immortal.
