Answer:
After the death of the Islamic prophet Muhammad in 632, a group of Muslims, who would come to be known as the Sunnis, believed that Muhammad's successor should be Abu Bakr whereas a second group of Muslims, who would come to be known as the Shia, believed that his successor should have been Ali.
Are you talking about this chart? If so, it appears that 30% of military deaths during World War I were Russian deaths.