An enemy paladin, encountered in Alm's route, as well as another completely new character for Shadows of Valentia. The rest is a quote from the Fire Emblem Wiki. 

"A noble general of Rigel, Berkut's father, who was Emperor Rudolf’s younger brother, died young. 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."

Berkut's english voice is Ian Sinclair. https://youtu.be/mspd1l2w_zo