Ríoghnán means 'king'.
Ó Súileabháin translates to O'Sullivan, which is interpreted as súildubhán, meaning 'little dark-eyed one'.
Ríoghnán’s father, an unnamed leprechaun one day decided to “experience” a day as a human, and acquired a polyjuice potion from the black market. By the evening, he ended up at a bar where he met Kathleen Ó Súileabháin. Unaware that the man who was hitting on her was a leprechaun, she had a drunken one night stand with him, which resulted in her becoming pregnant. Kathleen did not particularly care about the blood-purity of any child, considering she was half-blood herself, but she was in for a shock once he was born. She did not want to raise a half-breed, and definitely not a bloody leprechaun, but she did so anyway. She was vehemently opposed to everything that leprechauns stood for, and thus tried her best to raise Ríoghnán away from their influence.
Ríoghnán, as a baby, was fairly docile. However, as soon as he was able to walk, he wrecked havoc everywhere he went. He got into things he wasn’t supposed to, accidentally broke things, and often summoned leprechaun gold when it was completely inappropriate to do so. Kathleen became fed up with his antics, and thus purposely weakened him, by forcing him to wear cuffs made of iron. As he was very young when his mother started making him wear iron cuffs, he saw it as “normal”. He continued to function, as though he were a non-magical child.
Ríoghnán was climbing a tree at a park one day, when a high branch snapped, and he fell to the ground. The impact of the fall broke his cuffs, and his mother tried to reign him in. This led to his first act of magic at the age of 10, which was him temporarily paralyzing his mother’s legs so that he could run away. He was eventually found and caught by an Irish auror, who took him back to his mother, giving the conditions that he is to not be cuffed again. His mother agreed to the terms, only to break them a week later when she had new iron cuffs placed on Ríoghnán. Later that year, he received a letter to Hogwarts- which his mother is glad to let him go, as that means he is no longer her problem.
Ríoghnán, at Hogwarts, was sorted into Slytherin, although he does not know why. He found that he is fairly good at the theoretical and book-is aspects of magic, but he is unable to cast actual spells, as his attempts have ended up in fire.
Ríoghnán is the epitome of mischievousness and trickery, which is mostly due to his leprechaun half. He can be combative, daring, assertive, boisterous, and is likely to cross the line into being cruel. He is drawn to challenges and has a forceful will. Ríoghnán also has a strong flair for drama and style, and is a fast-moving, fast-talking person who has an appreciation for the finer things in life. While he typically makes things up as he goes along, he has no qualms about planning ahead for something BIG.
Although Ríoghnán can come across as brash, brazen, and overly exuberant, deep down he is very loyal and caring. He is observant enough to know when someone is upset, but he's more likely to offer support via a joke or hexing their enemies, rather than a big comforting hug (not that he is physically capable of a big hug anyway). Despite his trickster nature, he's not so daft or arrogant that he doesn't know when to stop fooling around and be serious. Ríoghnán is also quite intelligent, which shows when he is not fooling around. He often appears not to be listening to what somebody says, only to spring on them his knowledge of said topic, later on. Naturally though, he takes his knowledge and applies it to his pranks.
Due to his leprechaun genetics, Ríoghnán appears younger than he is. He also stands at a short 135 cm, compared to the average of 158.75 cm for his age. He also possesses the typical pointy ears of a leprechaun, as well as rich red hair.
• He owns a wooden Irish flute, which he plays when he is in any negative mood, particularly despair.
• Ríoghnán can summon leprechaun gold, which lasts up to one hour.