Although the Deep Blue Sea's deep waters were home to Hollow Void Demon Kings, the domain was ultimately swept through more than once by the Penglai Dao Lord.
Hollow Void Demon Kings were extremely rare in number.
In such a context, the presence of two Hollow Void beings, commanding a warship of the Heavenly Casualty War Hall, made them nearly invincible throughout the entire Deep Blue Sea.
Along the way, they were unstoppable, eliminating countless demons.
However, this high-profile journey was causing concern for a somewhat cautious Hollow Void War Immortal, "Although the deep sea isn't the frontline of the conflict between Penglai Immortal Sect and the demon race like the outer sea, from time to time Hollow Void Demon Kings sneak in, causing chaos. Our conspicuous approach could easily draw out high-rank demons to ambush us."
