Deep sea.
When the oceans first formed in ancient times, many lifeforms viewed the sea as a planet's mouth, one that would devour every creature that fell into it.
Moreover, this mouth possessed a certain deceptive quality. Countless marine creatures lived in the shallow waters near the surface, giving people a strong sense of safety.
However,
as the depth continued to increase,
so-called biodiversity began to disappear,
and the immense water pressure would crush and swallow any creature that reached this place.
For this very reason, the deepest parts of the ancient seas were often called dead seas. Since ancient times, they had swallowed countless lives... "Deathly silence" gradually became the defining trait of the deep sea.
Yet within such deadly depths, a terrifying group of marine creatures gradually emerged, known among the aberrations as the "Deep-Ones."
The Deep-Ones who first lived in the dead seas were nothing like the "gentle" beings they were now.
They lived in waters of absolute darkness and silence.
Since no other species existed there, food was exceedingly scarce... Any creature that fell into the dead sea would awaken their most primal hunger.
They would often even devour their own kind.
But as the ages changed, the Deep-Ones gradually rose toward the surface and evolved traits that allowed them to adapt to shallow waters... They could even gradually set foot on land, and food was no longer so scarce.
Their temperaments changed as well, evolving into a civilized race that ruled over the entire sea.
Even now, within the deep sea ruled by the President, there remained a true "dead sea."
Less than a hundred nautical miles from R'lyeh lay a massive pit leading to the dead sea.
Some Deep-Ones trapped by their limits and unable to make breakthroughs would try entering it in search