Leaf Faris Claus

リーフ・ファリス・クラウス, Leif,The Prince of Leonster (レンスターの王子),King of the New Kingdom of Thracia,Sage-Lord,Prince of Leonster

“My father's dying wish was to see the Thracian Peninsula at peace. And I'll do whatever I can to bring an end to King Bloom's reign. Even if it costs my life...”
— Leif

Leif (Japanese: リーフ・ファリス・クラウス Leaf Faris Claus) is the prince of Leonster, the son of the late Prince Quan and Ethlyn, and the younger brother of Altena. Left behind in Leonster as an infant while his parents travelled to Grannvale to aid his uncle Sigurd, he was forced into exile following his parents' deaths and the fall of Leonster at the hands of Conote, taken away by Finn of the Leonster knights. He was raised in hiding in the town of Fiana by Finn and, for a while, Lachesis, along with Lachesis's own daughter Nanna, and eventually joined the Fiana Freeblades led by Eyvel, protecting the village from bandits.

In the year 776, prompted by the kidnapping of Nanna and Mareeta, Eyvel's adopted daughter, Leif left Fiana to rally a resistance army to the Thracian occupation of the Manster District under the command of Raydrik, the duke of Manster, ultimately liberating it from the control of Veld of the Loptyrians. After his victories in the Manster District, he joined with the liberation army of his cousin, Seliph of Chalphy, to assist in freeing all of Jugdral from the iron grip of the Grannvale Empire, and went on to unify the Thracian Peninsula into the New Kingdom of Thracia with himself as its first king.

Leif is a playable character in the second generation of Fire Emblem: Genealogy of the Holy War, and later graduated to become the main protagonist of Fire Emblem: Thracia 776.

(Source: Fire Emblem Wiki)