Fire Emblem: Ankokuryuu To Hikari No Ken

Marth is prince of Altea and a direct descendant of Anri, the warrior who slew the shadow dragon Medeus. However, after an attack from the neighbouring kingdom of Dolua, Marth is forced to become an exile in the neighboring nation of Talis. His sister Ellis is taken hostage after his father is killed battling the evil priest Garnef. With the help of the Altean knight Jeigan, the Talisian Princess Shiida, and others, Marth embarks on a quest to find the sacred sword known as Falchion and the Fire Emblem that will allow him to wield it. Only then will he be able to confront Garnef and the resurrected Medeus, win the kingdom of Altea back, and rescue his sister.

from Wikipedia