Saias

Saias is a bishop of the Bragi Church with a high position in the court of Velthomer and one of the greatest tacticians in the history of Jugdral. He is kind and friendly to everyone he meets. As revealed in Chapter 22 of Thracia 776, Aida died protecting Saias from Manfroy, who sees him as a potential threat because of his Fjalar blood.

Some time after Mareeta falls victim to the Shadow Sword, Saias removes its curse and convinces her to get over fighting against Brigid, since she was possessed. He also convinces her to accept the Shadow Sword because she must love all blades to be a true swordmaster, and it becomes Mareeta's Sword, a personal weapon for her. In Chapter 23, Ced gives the Bragi Sword to Saias, who in turn passes it to Leif.

He appears twice as an enemy prior to his recruitment and his presence greatly boosts the fighting abilities of his allies, since he is very charismatic. If Ced is recruited during Chapter 23, Saias will leave Leif's army to travel to Bragi Tower without giving his reasons as to why.

After the liberation war, his talent is recognized by Seliph, and Saias enters the service of Grannvale. He also greatly contributes to its reconstruction.

(Source: Fire Emblem Wiki)