|“|| We all have secrets. And reasons. And many of us have earlobes.|
Are you trying to be funny?
No, I am succeeding.
—Ronodin, to Kendra
Ronodin is the first and only Dark Unicorn, briefly mentioned by Bracken in Keys to the Demon Prison as a Unicorn who willfully corrupted his horns with dark power, and again in Dragonwatch, where he is mentioned to have been seen at Soaring Cliffs. In Wrath of the Dragon King, he makes his first physical appearance at the Feast of Welcome and provides valuable information to Celebrant and his Dragons. He meets Kendra and Seth in human form, expressing a desire for Bracken's First Horn, which Bracken left in Kendra's possession, as well as an interest in Seth for being a Shadow Charmer.
Ronodin is the nephew of the Fairy Queen. He claimed to have had a sister, whom Kendra reminds him of. At some point, he apparently became enamored of darkness and willfully corrupted his own horns to take on dark power... and then abandoned his horns, deciding he wanted nothing to do with his heritage (but would in time come to see this decision as his greatest mistake). He apparently had a role in the downfall of his uncle, the Fairy King, which resulted in his uncle's capture by Gorgrog though everyone thought the Fairy King was killed.
Ronodin then vanished and began doing favors for the Underking in order to reclaim his First and Second Horns, which somehow came into the Underking's possession.
In human form, Ronodin appears as a young man in his late teens with thick dark hair, intense dark eyes, and wears a dressy black robe of Asian design with subtle touches of embroidery at the neck, near the wrists, and around its fancy buttons. His nose is described as looking crooked, as though it had been broken once or twice, and he has a faint scar through one eyebrow.
In his unicorn form, he has a dark gray coat, fiery mane and tail and his horn glows orange like metal that has been heated up, and his blood is reddish-gold.
A dark and sly individual, Ronodin shows all the signs of a narcissist, presenting a self-righteous attitude, refusing to acknowledge his own wrongs, at least not sincerely, or regret his misdeeds. He is smug, confident, knows how to push others' buttons, yet he never tips his hand, saying overconfidence is clumsy. Ronodin is known to not align himself with anyone and any ties he has to someone he will readily sever once he decides those ties are no longer useful or become a hindrance.
Later during his time mentoring Seth Sorenson Ronodin also reveals the true extent of his malevolent and manipulative personality, having taken advantage of the latter's amnesiac state to manipulate him to accomplish his own ends, willfully endangered Seth by getting him indebted to the Underking to insure he could not escape, and use him against his own family.
Ronodin spitefully holds his own family in contempt, especially his cousin Bracken, whose horns Ronodin had intended to corrupt in order to weaken his cousin. Ronodin despises the likes of his cousin, calling him and those like him the 'light-makes-right brigade', telling Seth more than once that dark beings like himself (and Seth) are unjustly persecuted by beings of light and using rhetoric to illustrate his point that darkness isn't inherently evil (which has some truth to it).
However, it's all a façade that he uses to conceal his truly wicked and sinister nature, such as when Kendra calls him a monster he responds that she has no idea. This is also evident when he cruelly warns Seth that the boy's actions have resulted in great harm, despite his coercion and being exploited, and claiming that Seth's friends and family will lock him up for the misdeeds he was made to do, disregarding the facts that Ronodin exploited Seth and endangered his life more than once to use him for his own ends.
Ronodin appears as a personal guest of Celebrant at the Feast of Welcome, where he meets Kendra and Seth for the first time, in his human avatar. He insinuates to Kendra that he has Bracken and offers advice to find him if she gives him Bracken's First Horn which is in her possession; Kendra blatanly refuses. He speaks with Seth, noting that Seth is a Shadow Charmer yet his powers are woefully underdeveloped, offering to mentor Seth to reach his full potential. Again he is refused but takes it in stride, and he tells them both that the Dragons' victory is guaranteed. He also compares Seth to himself by claiming he had a sister whom Kendra reminds him of.
He speaks with Kendra again when she is captured by Jaleesa and brought to Celebrant, offering to help her escape if she gives him Bracken's First Horn and even the knowledge he shared with Celebrant, only to be refused again. Although he doesn't reveal the big secret as to how the dragons will win, he uses rhetoric to explain why he sides with them to illustrate his certainty that Kendra's side is doomed to failure.
In the end, Ronodin arranges for Seth to be kidnapped by Mendigo (who had been tampered by Vernaz) and brought to him, where he teaches Seth how to quench fire and gleefully looks forward to the work they'll do together.
Ronodin continues to mentor Seth, exploiting the boy's amnesiac state and getting him in debt with the Underking to insure Seth can't escape so that he can use Seth for his abilities as a Shadow Charmer. At the behest of the Underking and to aid Celebrant, Ronodin sends Seth to Wyrmroost to meet the Sphinx, who helps Seth unleash the denizens of the Blackwell, resulting in the the fall of Wyrmroost.
During his confrontation with Kendra and Bracken, he reveals that he holds a great amount of resentment and anger towards his family and even more animosity for his cousin, having openly insulted and mocked his uncle's long imprisonment and suffering by the demons for the sole sake of infuriating the latter and taking absolute glee at the fact that he had somehow played a part in the Fairy King's capture. Ronodin explains how he reacquired all three of his tainted horns from Celebrant and the Underking in the hopes of corrupting Bracken's three horns. Before the duel, he took the second from Bracken at Soaring Cliffs and obtained the third from the Font of Immortality. Whether Ronodin personally retrieved and broke the Font remains unknown.
They do battle in their unicorn forms, fighting each other ferociously until Kendra helps Bracken by giving him an energy boost. This allows Bracken to break off Ronodin's horn, forcing him back into his human avatar, and then purifying Ronodin's Third Horn, much to his outrage. He swears to make Bracken pay before using a potion to transform into a large raven and make his escape.