Though the appearance of the Hadal Hell had to do with the Netherdark Hell, the ultimate reason why the nine worlds had become part of hell was due to hellfire.

The very same Hadal Flame that Lu Yun controlled.

Based on the information in Violetgrave, the Netherdark Hell was the first of the five hells to appear. Since it buried civilizations and the collective wisdom of the living, it was ranked first among the five.

……

As Lu Yun wielded Violetgrave, a haze of violet radiance dyed his long black hair into crystalline purple. The Tome of Life and Death absorbed the transparent Netherdark Flame and permitted it to take root within itself.

The next time Lu Yun entered the fourth realm, what would...