Berkut

Berkut is a non-playable character who appears exclusively in Fire Emblem Echoes: Shadows of Valentia. He is the nephew of Emperor Rudolf of Rigel and a major antagonist in Alm's route.

A noble general of Rigel, Berkut's father, who was Emperor Rudolf’s younger brother, died when Berkut was around 10 years old. Being so timid as a child that even riding a horse would make him cry, his mother raised him strictly so that he would not be teased for being fatherless, and to become a man worthy of becoming the next emperor, until she also passed away before he reached adulthood. Viewing Emperor Rudolf as a surrogate father figure, he developed an interest in devoting himself to the military, in order to seize recognition for his deeds.

He guided the coup d'etat in Zofia by luring Desaix into betraying his homeland. Berkut also convinces Fernand to join the Rigelian army after leaving the Deliverance. He is vying to be the next emperor and commands the invasion of Zofia to prove his military prowess. He is also engaged to Rinea, who cares for him during the ongoing war. According to Lukas, he is around the same age that Alm is.

(Source: Fire Emblem Wiki)