Ishvalans

Natives of Ishbal are characterized by their brown skin and red eyes. They are a deeply religious people who reject alchemy (which they call "The Grand Arcanum"), a process that humans use to understand, decompose, and rearrange matter into a different form. The Ishbalans feel the science of alchemy is a sin because it insults their God, Ishbala, by implying that humans can better His creations. Ishbalans also despise the military of Amestris, most outsiders and Ishbalan exiles who were banished because they practiced alchemy.

Society
Ishbalans, they are less opposed to alchemy than their anime counterparts, but still think it against nature and their God, which they call Ishbala.

Massacre
The massacre of Ishvar 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 Ishvar Massacre in Ishbal was started by the Homunculus Envy, posing as an Amestrian soldier, not Sloth.