Karel

Karel (カレル, Kareru?) is a Sacaen swordmaster who has taken two titles over his career, the insane "Sword Demon", and the benevolent "Saint of Swords".

Rekka no Ken
He lives only to find challengers worthy of his blade and will kill said opponents in battle without remorse or hesitation. To obtain the infamous Wo Dao, he has killed all his family, except his sister. His feats — including fighting Bern's armies alone and slaying a wizard that could freeze blood in a person's veins — have earned him infamy across Elibe, as well as the title of "Sword Demon". He is Karla's older brother and eventually teaches Guy some swordplay, and discovers that he is unwilling to kill them.

Fire Emblem: Fūin no Tsurugi
Karel is now the uncle of Fir, the daughter of his late sister Karla. He is now retired and travels the land with a new nickname, "Sword Saint", and resolve, having finally found peace in himself after many years.