Brigid is Ríoghnach's elder, full-blooded sister. Ríoghnach absolutely adores her. When Ríoghnach was little, her family would sometimes call her "Brigid's little shadow" because she followed Brigid around everywhere. Nowadays, Ríoghnach is far to old and prideful to do that but she still mimics her sister, although more discretely.
Fáelán is Ríoghnach's brother and best friend. He knows her better than anyone does — they've spent so long together. They're "the little kids" in their family, but between the two of them, Ríoghnach is a year older. Sometimes talks down to Fáelán because of that, but she does it because it makes her feel better, not to make Fáelán feel worse. She takes him for granted, but she needs him. More than anyone else, she needs him.
After Fáelán, Caitríona is Ríoghnach's next closest sibling in age. She doesn't idealize her the way she does Brigid; she sees Caitríona more clearly for who she is. The two of them are the Ravenclaw — word-loving Ravenclaws, giving them their own special bond. For example, that love of words branches over into names, and while most of the family calls her sister Cáit, Ríoghnach usually uses Caitríona's full name. Ríoghnach trusts her — perhaps it's because she knows when she tells her something, Caitríona will understand what she's trying to say.
Cadeyrn's the sibling who's most distant. For one, Ríoghnach and Cadeyrn were separated for many years, with him at Hogwarts and her at home. And moreover, they don't have a shared thing that bonds them. In their family, the kids are sorted into categories three ways: by gender, by age, and by mother, none of which put Cadeyrn and Ríoghnach in the same category. And for another, he's 17 now; a man grown, and about to leave school — to leave her behind. Ríoghnach doesn't even want to think about this, and it's easier to get angry at Cadeyrn — to try to hate him, so she can be ok with him leaving.
Clíodhna is Ríoghnach's own mother. While she sometimes declares Clíodhna her favorite parent to hurt her father or Enat, she has never declares Enat or Cináed her favorite parent to hurt Clíodhna. Ríoghnach loves her mother and hates her — respects her and scorns her; fears her, but also looks to her for protection.
Enat is Ríoghnach's other mother, step-mother, secondary mother. While Ríoghnach is less close to Enat than to Clíodhna, Enat is absolutely her mother too. Ríoghnach is less close to Enat than to her own mother, but the flip side of that is that generally, they get alone more peacefully.
Cináed is the most distant of Ríoghnach's parents; her mothers take care of her. Cináed is always at Eoghan's side, being instructed. Ríoghnach knows he takes no joy in his role of endlessly listening to Eoghan, but it's a fact of life. Unlike some of her siblings, Ríoghnach doesn't hate their father; never more than a moment's flash on anger. Eoghan is pulling him around, and
Ríoghnach fears her grandfather. Not terribly so, but a little niggling that never goes away. It has something to do with the fact that her mother and father married to prevent a blood feud — Ríoghnach is too much Clíodhna's daugher. Not that she would ever want her aunt to be allowed to kill her grandfather, but the fact that he killed his brother doesn't sit easily with her. The mere idea that they were once like her and Fáelán always makes her skin crawl.
Bríd is Ríoghnach's grandma. Well, not by blood. Her real grandma, Dearbháil, died when her father was little. After her death, Eoghan remarried. Bríd is Cináed's step-mother, Muiris's real mother. She's wonderful to them all, and Cináed even named his first daughter, Brigid, after her.
He's Ríoghnach's uncle; her dad's little half-brother. In many ways, he's the most fun of the adults — perhaps because he's an uncle, not a parent, so he doesn't have the responsibility of chiding Ríoghnach.