Cocytus is one of the eponymous Underworld river gods of the same name. The others are Styx (Hatred), Pyriphlegethon (Fire), Lethe (Oblivion), and Acheron (Pain).
Cocytus, aside from being the god of his own river, is the god of lamentation, tears, shrieking and wailing.
Those who had not been given the correct funeral rites upon their deaths were said to travel without hope along Cocytus' bank for a hundred years, and would have great sorrow about their predicament.
Cocytus' water is freezing cold, filled with millions of heartbroken voices, as if the river were made of distilled sadness. If dipped in, the person's thoughts will become sad and miserable, having no purpose to live.
Children of Cocytus have the ability to release a high-pitched wail that deafens and disorients anyone within the vicinity for a short period of time; however, it cannot differentiate between friend or foe. The longer the sonic wail is maintained, the more energy it drains.
Children of Cocytus have the ability to croon a dirge, a song of lamentation and grief, which causes anyone hearing it to fall in a state of depression, leaving them vulnerable to attacks. Prolonged use will drain the user severally.
Children of Cocytus can induce the roots of lamentation on others and make their enemies woeful and miserable, which causes their combat and social abilities (as they become less able to interact with one another out of grief) to become very sloppy and rusty for a short time. The affected will become invulnerable to further effects of the power for a moderate time.
Children of Cocytus have the ability to create a field of energy that releases a loud shriek that can disorientate the sense of balance of anyone that hears it. The effects last for about half a minute at most before the affected regain their equilibrium. The longer the field is maintained and the larger its radius, the more energy it drains.
Children of Cocytus can enter and exit the Underworld as they please.
Children of Cocytus are highly resistant to the effects of the River Cocytus.
As their father was an Underworld god, children of Cocytus are able to communicate with the dead and wandering souls, hearing their voices as echoes, whispers, and screams.
Children of Cocytus have the innate ability to generate tears without any need for physical/emotional stimuli, as Cocytus' river was also called as the river of tears.
Children of Cocytus have the ability to Shadow Travel, a sort of teleportation, for their father was the god of the dark waters of the River Cocytus. The larger distance covered by the user, the more energy lost.
Children of Cocytus have the ability to temporarily alleviate lamentation from someone, including its causes (sadness, melancholy, grief, etc).
Children of Cocytus are able to release high-pitched screams in order to shock fear in others, vibrate objects, or even drown out all sounds in order to hear the voices of the dead much more clearly.
3 Months After a Character is Made
Children of Cocytus have the ability to curse water to become freezing cold, turn the person's thoughts sad and miserable, and also forces the person to hear the millions of heartbroken voices of the River Cocytus, all of which when the person touches the water. The effects will subside after a short while and renders the victim immune to further effects of it for a moderate time.
6 Months After a Character is Made
At this time of training, the high-pitched screams of children of Cocytus are able to reach an amplitude that cannot only deafen others, but may cause nearby objects and structures to rattle, vibrate, shatter, crumble, or even explode. However, it cannot fully destroy anything that is 3 or more times the size of the user, and the larger the object, the more it drains them.