The Lord of the Deep is a colossal cephalopod-like malevolent eldritch monster, which is 1000s of years old. One thats over 500 ft tall and 900 ft in diameter, with numerous tentacles. It's primary ones can stretch 1000s of miles and are almost 100 ft thick with 100s of tentacles at the end. Some believe that is the originator of the Kraken myth of pre-Cataclysmic Earth.
It's a incredibly powerful entity with great magical and psionic powers, in addition to regenerative abilities and super strength. Capable of surviving a 82 megaton nuke, though with grievous wounds. The Lord of the Deep is a psychic vampire that feeds on the negative emotions which are generated by its dying victims. It's an entity which travels from dimension to dimension, consuming worlds. Its home dimension is a pocket dimension, a realm of water.
Sometimes it will send out tentacles vast distances to capture victims which it drags back 100s or 1000s of miles back, kept alive by its magic. Which it then kills or turns into abominations. Using its magic to merge its victims to the lifeforms of the sea, thereby creating monstrous hybrids. Magic, wooden weapons, holy weapons, and runic weapons inflict far greater damage on it than plasma cannons, laser beams, explosives, missiles, or other weapons.
Background[]
The Lord of the Deep visited Earth thousands of years ago, before Egypt and Sumeria, when due to the Atlantean cataclysm, magic was disappearing from the world. It had opened a rift to Earth, and right through it came the Lemurians who were fleeing Earth, trapping it on Earth for 1000s of years. It would give rise to the Kraken myth of pre-Cataclysmic Earth. As magic slowly but steadily disappeared, it weakened and eventually went into a slumber. Upon the cataclysmic return of magic to Earth in the early 21st century, he began to slowly awaken.
Now it terrorizes the sentient inhabitants of the sea and coastal regions along the Pacific Rim. Killing and mutating 1000s, most likely far more. It has established its own dark dominion in the western Pacific, south of Japan, east of China, and north of Indonesia. A domain which is steadily growing, both dimensionally and physically. Which is defended by its army of monstrous abominations, whom terrorize the seas, raid neighboring communities, and kidnap victims. In opposition to it is the time displaced American navy, the seaborne civilization of the Lemurians, and sentient dolphins, orcas, and whales. The Splugorth lord in the island-continent of Atlantis is aware of its existence and is monitoring its activities, and so are the various Vampire Intelligences on Earth.