Scar's Master

This wise man, called only "Master", is a former Warrior Priest of Ishval who mentored the young Warrior who would go on to become the infamous serial alchemist killer Scar. When the Ishval Civil War came to a close, Scar and his Master were separated and the wise priest took refuge in the South of Amestris with other evacuees, but increasing State Military presence drove him east to avoid confrontation. Hearing the vicious exploits of his former pupil, he appears before Scar in Chapter 26 and warns him that his senseless vengeance will only bring about more senseless vengeance, perpetuating the cycle. He tells the younger man that he understands his hatred for State Alchemists, but that - for the time being - he must endure that hatred and keep it from turning him into a beast, a message that (though he continues on his swath of revenge) Scar remembers multiple times throughout the series. Scar's Master returns again when Ishvalan refugees are asked to help in the attack on Central City just before The Promised Day.

In the manga, Scar's Master had a black mustache, making him the only fully Ishvalan character with a hair color other than white or silver, but in the 2009 anime, his mustache color was changed to match the others of his ethnicity.