Once emerged from Harthatenarl's remains, the Original One became pregnant after mutating into human form and grew fond of her offspring, contradicting her otherwise eldritch origins. Born aeon, immortal god-like beings resembling humans, the triplets share their mother's physical traits, such as the complete lack of color in their hair and skin, reddish eyes with icy blue sclera, fangs, as well as an organ connected to their spinal cord capable of granting them flight. Ryūnosuke, Shūji and Sōseki, in contrast to their mother's title, are often collectively referred as the Children of Eon, and are known for their strength, as well as their ethereal beauty and contrasting personalities.
The identical triplets were born from Eon, the Original One.
Sōseki is the third son and the youngest of the trio, as well as the main protagonist of Right to Die: Reign Ruins. The defiant figure of the family, he keeps his hair down yet partly shaved, and wears flashy leather outfits with spikes and studs. His main color is red, he is a guitarist and prefers to fight with firearms in battle. He is laid back, gruff, wild and rather unpredictable, joking around and making light of serious situations, and has a flippant attitude and an abrasive, sarcastic personality, often coming off as rude. He jokingly flirts with attractive people he sees and enjoys reading fashion articles with flashy models.
Sōseki's fighting style is flamboyant and often improvised depending on his immediate surroundings. He loves taunting his opponents and showing off fancy moves during battle. He usually wields his favorite sword, Oiwa, a nodachi, an heirloom from his mothers, and his trademark handguns, though he has also used a diverse set of weaponry. A running gag in the series is that he sometimes breaks swords he uses, prompting him to fight with swords cut in half.
Sōseki absolutely adores his human mother, Zdenka, but he has a strained relationship with Ena. Even if he does care about hers, he sees his existence as being a mere extension of her, and is reluctant to take the responsibilities of his heritage, including those who seek revenge on Ena by trying to kill him. He feels completely disconnected from her alien morality and ruthlessness, although he did inherit her desire to protect humanity.
Shūji is the second son, serving an ambiguous role as both a supporting character and an antagonist of Right to Die: Bleed Black. While not as radical as Sōseki, he wears casual clothing but has a sophisticated dress code, and he keeps his hair down yet spiky. His main color is purple, he is a pianist and a model, and wields a sword with a dagger. He is friendly, caring, sweet and talkative, of a patient nature and a mature, focused and playful personality.
Ryūnosuke is the eldest of the trio, being the main antagonist of Right to Die: Reign Ruins. Perhaps being the most old-fashioned one of the family, he wears refined clothing made of silk that looks modest next to his brothers' and keeps his hair swept back. His main color is blue, he is a bassist and he has an affinity for melee weapons, as he views firearms as crude and undignified weapons. He is a withdrawn young man of a calm, yet arrogant personality, as well as being cold, calculating, ruthless and unemotional, possessing a chilling demeanor, although he occasionally shows a dry sense of humor when annoyed.
Ryūnosuke's fighting style is notable for its speed and range, as he can move his sword faster than the eye can see with his superhuman speed. He is shown to be strongest fighter amongst the three brothers, possessing the most victories out of his battles against Sōseki and being easily able to disarm and subdue Shūji. Ryūnosuke is an honorable warrior, as, aside from his dislike of guns in general, he despises fighting dirty and refuses to attack opponents from behind. He is also very disciplined, usually preferring to use only his katana, Okiku, as his weapon of choice.
Whereas Sōseki is preoccupied in keeping his humanity, Ryūnosuke is obsessed with obtaining power. He greatly admires his mother, wishing to surpass her in strength and righteousness. He believes humans are weak and frail, and he became a doctor after witnessing the near death of his human mother, Zdenka, and blames himself for what happened to her. He possesses an extreme dislike of humanity as a whole, and keeps his emotions in check in an attempt to distance himself from them.
A major driving force in the Right to Die storyline is how different the brothers are despite being identical triplets. They are remarkably different in tastes, fighting styles, personalities and goals and Sōseki and Ryūnosuke themselves spend much of the story fighting with each other. They seem to represent the several sides of Ena's morality under Zdenka's influence — she is ruthless like Ryūnosuke, rebellious like Sōseki and playful like Shūji. This is reflected in her rainbow color scheme.
Appearance-wise, the triplets are based on African-American albino and openly gay model Shaun Ross.