In the first layer of hell, Aphnas, the eternally burning flames and ceaseless battles were the themes of this hell.
As the Lord of the first layer of hell, Zariel's personal preferences greatly influenced the atmosphere of hell. Of course, it also related to the geographical location of the first layer of hell.
Theoretically, the first layer of hell was hell's entrance and exit; any devil who wanted to leave hell in their true form had to pass through the first layer. The battlefield of the blood war between the Abyssal Demons and hell was located in the Blood River Fortress on this level.
Zariel became the master of the first layer of hell also because of his belligerent nature.
Other Lords of Hell genuinely wouldn't be able to sustain the constant and eternal bloodshed.
But recently, Zariel, who treated war as daily entertainment, had not visited the Blood River Fortress for a long time.