General
The eerie aphotic leviathans are seldom seen at the surface, dwelling hundreds of meters down in the oceans' deepest trenches. Glowing sacs all around their bodies contain tiny organisms -- the same organisms responsible for the light of the Candle Archipelagos waters -- that attract shrimps and other small creatures to them. When something large enough comes along, the leviathans contract and extend their phosphorescent sacs to create pulsating displays of light. The light disorients the larger creature so the leviathan can rush up and swallow it whole. While they're the bane of the deep trenches, the lack of food that far down limits the size of the leviathans, so it's rare to find even a female longer than a few feet. They can still deliver a nasty bite to any deep sea-exploring magi who wanders too close.
Egg
This egg pulses in the dark like a firefly.
Hatchling
Aphotic leviathan hatchlings are tiny and mostly helpless, spending the first few weeks of life adrift in the ocean currents. They have large heads and will gobble down anything within reach, much like the adults, but their underdeveloped fins prevent them from actively chasing prey down until they get larger. It's not uncommon for the currents to send the leviathan fry up to the surface, even though they live at the depths as adults. When their fins start to grow in and they can swim against the current, their teeth grow larger and they start to hunt as active predators. Eventually, they'll gain control over their photic sacs and descent to the depths of the ocean where they can use the lights to manipulate their prey.
Adult
No one is quite sure whether aphotic leviathans and their close relatives the coronate leviathans are fish, reptiles, or some combination of the two, but they're impressive animals regardless. At least, the females are impressive. Serpentine in shape with long, sharp teeth and a brilliant lure on her head, the female aphotic leviathan can reach ten feet or more in length. The male, however, is rounder and typically only about a foot long when fully grown. While both male and female leviathans can deliver a nasty bite and use their lights to disorient prey, the females are by far the more aggressive of the two. The size difference means that a careless male could easily be eaten by a hungry female, so finding a mate is a dangerous affair for the males. They use their lights to charm a potential mate to win her favors, swimming in circles and fluttering their fins as a sort of dance. If he does a satisfactory job, the female will allow her to accompany her for a few days, though he must be careful not to linger too long or he might end up nurturing her eggs as an unintended meal.
Notes
Obtained from: Donation (Aug)
Breeding: Yes
Renaming cost: 2000 gold
Release date: August 1st 2018
Element: Neutral 
Breeds with the following:
Aphotic Leviathan + Aphotic Leviathan = Aphotic Leviathan (Guaranteed) Cost: 3 shards
Coronate Leviathan + Aphotic Leviathan = Coronate Leviathan (Guaranteed) Cost: 3 shards
Coronate Leviathan + Aphotic Leviathan = Aphotic Leviathan (Guaranteed) Cost: 3 shards
August 2018 5-shard Donation Pet
Sprite art: Lazuli | Description: PKGriffin