Ishvalans

Natives of Ishval are characterized by their brown skin and red eyes. They are a deeply religious people who worship the creator god and god of the earth Ishvala. One of their warrior priests who later became known as Scar viewed alchemy as blasphemous to God because he felt that it turned a creation of God into a degenerative form. It has not been made clear in the manga whether other devout Ishvalans shared his personal beliefs, although a few Ishvalans, including Scar's brother, have been shown to have an interest in alchemy. In the anime, however, it has been clearly stated that Ishvalan religion forbids alchemy, their attitudes towards it and those who use it (i.e. the Amestrians) being a reason for conflict between the two peoples.

Massacre
The massacre of Ishval in the manga was not used to create a Philosopher's Stone, but rather as one of required points of bloodshed to make a node of the Transmutation circle of Amestris. The Ishval Massacre in Ishval was started by the Homunculus Envy, posing as an Amestrian soldier.