One of Deep Sea Demons types easily identified by their gigantic dimensions.
Behemoths with vague resemblance to Nest Mothers but with dense armor which covers their entire body and a large mouth the size of a capstan.
They are known to the demons as Mountain Devourers due to their size and might. They evolved from Nest Mothers to be the Deep Sea Demons' main force, being able to produce a battlefield suited for them in exchange for losing their ability to produce Demonic Beasts and Demonic Hybrids.
Though they were known for a long time by the Demon Civilization, the humans only became aware of their existence after the alliance between the two races ocurred. It is first mentioned during one of the General Staff's meeting inside the Eleanor Skycruiser  and is eventually seen while fighting the First Army in the Bottomless Land and while fighting Nightingale and Serakkas.
- Even though they are powerful, their numbers appear to be the lowest compared to all of the other types of Deep Sea Demons.
- Chapter 1479
- Chapter 1474-1475
- Chapter 1483