King Garon: King of Nohr, father of Xander, Camilla, Leo, and Elise, and stepfather of Azura. His retainers are Iago, Hans, and Zola.
Sumeragi: Former King of Hoshido and father of Ryoma, Hinoka, Takumi, and Sakura. He was killed by King Garon's soldiers sometime after Corrin's birth.
Mikoto: Current Queen of Hoshido and mother of Corrin. She married Sumeragi after his first wife, Ikona's death.
Saizo and Kagero: Ryoma's retainers. Saizo has a twin brother named Kaze. Kagero was formerly one of Mikoto's retainers.
Azama and Setsuna: Hinoka's retainers. Azama is an aloof monk with nihilistic views on the world. Setsuna is an absent-minded archer who often daydreams.
Hinata and Oboro: Takumi's retainers. Hinata is a cheerful and easygoing Hoshidan samurai. Oboro is a Hoshidan spear fighter seeking vengeance against Nohr due to the death of her parents.
Subaki and Hana: Sakura's retainers. Subaki seeks perfection in all he does. Hana is one of the finest katana wielders in Hoshido.
Laslow and Peri: Xander's retainers.
Laslow is good at dancing, though not as skilled as Azura. Peri has a peculiar personality due to childhood trauma.
Selena and Beruka: Camilla's retainers. Selena speaks in a condescending manner to others, though she's known to mean the opposite of what she says. Beruka is a skilled assassin orphaned at a young age.
Niles and Odin: Leo's retainers. Niles is a former thief and currently an archer. Odin is a dark mage who often names his weapons.
Arthur and Effie: Elise's retainers. Arthur is a self-styled "Hero of Justice". Effie met Elise when she was young, and the two quickly became friends.
Flora, Felicia, Jakob, and Gunter: Corrin's retainers. The reason why Corrin has more is because they change depending on Corrin's gender. Idk why that's just how it is.