Erebus

Erebus is a minor character in the Elysium'verse who has never made an actual canonical appearance within our OC world, save for his background role as the father of half of our existing cast (as well as generally half of the deities in the Underworld).

One of the four Primordial Beings of the universe spawned by the entity Chaos in the beginning of time, Erebus is the deity of All Darkness and Shadow. He is and always will be everywhere and nowhere.

=Appearance= Unknown! Very few have ever seen him.

Erebus lives in the walls and every corner. He is maybe made of shadow, or not. He is probably tangible, based on his ability to sire children, but... maybe not.

=Personality= ...Unknown, very few have ever met him. This is including his parade of hundreds of children, whom have each been born and basically left with Nyx to pile on top of each other and fend for themselves. Presumably there's something endearing in his mystery personality that inspires Nyx to happily stay with him as his wife and mother of his children throughout the past millennia, but she respects his mysterious privacy and won't ever share those details with you..

One can assume that he does not possess any sort of paternal traits.

=Family= Erebus' background is basically the same as it is within the mythological source material. Chaos, who created the universe, next spawned four Primordial Beings to form the world; the Sky, the Earth, the Night, and the Dark. Erebus (the Dark), descended to the Underworld with his sister Nyx (the Night), and the two of them married and began to populate the Underworld with their offspring.

(Sorry, take it up with Ancient Greece.)

The children of Nyx and Erebus, by this time in the modern day, number presumably into triple digits. Their kids are responsible as daemon personifications for all sorts of "darker" traits and actions; they include entities of Death, Aging, Insanity, Sorrow, Decay, Nightmare, Sleep, Dream, and so on and so forth. Ker, Goddess of Violent Death, and the first Death Incarnation, is one of their first born children. Nyx and Erebus have been spawning offspring since the dawn of time, and most of their children sprawling throughout the centuries either don't get along with each other, or have intermingled as their own couplings true to the nature of the Greek pantheon. Or both! The House of Nyx is a chaotic mess.

For Erebus' own part in this, he has taken a notoriously absent role in the upbringing of his own children, in the sense that despite being ever present and always existing in the recesses of Nyx's own home, literally most of their children have never met Erebus. Nyx has never seemed to mind this, content to keep pairing with him to add babies on top of babies, and delusionally priding herself on their big happy household.

The physical and emotional absence of Erebus as a parental figure plus Nyx's failings as a parental figure herself has impacted the adulthood and behavior of many of their children, particularly in reference to unhinged villain Thanatos, who was able to prey on his own siblings unsupervised since toddlerhood. In fact, many of Erebus' children are inclined towards violence and general monstrous traits, which he... probably knows about? But has apparently not cared about enough to be present. The opinions of his children about him range from indifference to resentment. Again no one really knows how he feels about this, as his own opinions about his children seem to range from indifference to... apathy? Who knows.

=Trivia= The darkest part of the Underworld is an area named after him, also called Erebus.

Mythological roots
Erebus is one of the few Elysium characters who is functionally almost the exact same as his mythological counterpart, only with some contextualization added to relate to our more fleshed out cast. For more information on Erebus in Greek mythology, please visit his Theoi page.