Whitewings Sisters

Whitewing Sisters is the family ship between Palla, Catria and Est from the Fire Emblem fandom.

Canon
Palla, Catria Est are three sisters from Macedon. Palla is the oldest, Catria the middle sister, and Est the youngest. Their parents died when Catria and Est where very young and Palla had to take care of them. They became pegasus knight of Macedon. They created a powerful combat technique called triangle attack that they could execute together. Minerva, the princess of Macedon, created a group of knights called the Whitewings composed of her and the three sisters.

Fire Emblem: Shadow Dragon
Machialis, the prince of Macedon, killed his father and become king. He decided to ally with the Dolhr's alliance. However his sister Minerva alongside the three sisters disagree with him and want to join the Altean army. But to force them to fight in his army Michialis took his youngest sister Maria hostage, When Marth saves Maria, Minerva joined his army alongside Catria and Palla. Both Palla and Catria develop unrequited feelings for Abel (a knight from Altea) and Marth respectively. Est joins them latter after stealing the sword Mercurius. Est (not knowing her sister feelings) fell in love with Abel. After the war Palla and Catria returned to Macedon, while Est married Abel and moved to Altea.

Fire Emblem Echoes: Shadows of Valentia
After the War of Shadows, Est is kidnapped by pirates and bring to the continent of Valentia. Palla and Catria cross the ocean to save her. In Valentia they meet a priestess Celica (who is in fact the heir of the Zofia throne) who was on a mission to the Temple of Mila, but before decide to stop action the pirates. They join her army, kill the pirate's leader Grieth, and liberate all the people that were imprisoned in his fortress. Est finally reunites with her sisters. They all decide to stay in Celica's army to thanks her. They end up by participated in the battle against the mad god Duma. After the end of the war and the unification of Valentia they return to Archanea.

Fire Emblem: New Mystery of the Emblem
A rebellion against Minerva's rule breaks out in Macedon. Catria joins Marth's army to restore the order at Macedon. Palla, who was forced to flee, joins later. When they return to Altea, Est is held hostage by the Archanean army to force Abel to fight for them. She is freed by Marth army and joins alongside her husband. After the war, Catria and Palla work to restore Macedon, while Est vanishes, leaving her sisters and her husband. Abel searched for her.

Fire Emblem Warriors
While Palla, Catria and Est don't appear in the Fire Emblem Warriors spin-off, they are mentioned in Cordelia and Ceada's support conversation. Cordelia (who comes from the same world as the Whitewing Sisters but two millennia later) asks Ceada (who has fought alongside the sisters in the War of Shadows) if she knows the Triangle Attack (which is considered to be a legend in Cordelia's time). Caeda answers that she has seen the sisters performed the Triangle Attack but never learned how to do it herself. They agree to try to recreate it with Hinoka, another pegasus knight. And if all three of them achieve A-supports with each other, they will perform the move as part of their Awakening special attack.

Fire Emblem Heroes
All three Whitewing sisters appear in Heroes in their New Mystery, Echoes, and Spring attire. Additionally, the three of them as young children appear in a Duo Hero led by Palla with Catria holding Est as a cohort. One could call them a "Trio Hero". At the time of writing, they are the only Heroes to hold this distinction.

Fanon
The Whitwongs Sisters are quite popular within the Fire Emblem fandom. This is due to the fact that they are some of the most recurring playable characters in the series. They are considered to have served to create the archetype of the three pegasus sisters. Palla and Catria are popular for being responsible and strong but Est is sometimes criticized because she is a unit hard to use, has been captured thrice and because she left her family. They are also liked because they are the only characters that can perform the Triangle Attack in the games they appear in.

Fandom
TUMBLR