One of the many messianic figures that troubled the Brazilian government in the late 19th century. Born in a poor family of cattle breeders, through hard work and dedication Antônio became a teacher and lawyer, and married Brasilina Laurentina de Lima, with whom he'd have two children. However, after being cheated on by his wife, he abandoned his family and began to wander through the arid and deserted Brazilian Northeast.
No one knows what happened to him during his wandering. If asked, he'll claim that he "met with God", and God told him that he'd lead the people to the Promised Land, and gave him the power to heal. After 4 years isolated, he returned to civilization. He advised and preached to the poor and miserable in villages and farms, telling them of the evils of the government and the Catholic Church, and that there was no need to be slaves to the rich. He attracted admirers and followers who wandered with him. In a few years, these followers were in the thousands, and considered Antônio a saint, a messiash sent by God to save them.
Together, his followers built a village in an abandoned farm, named by him Belo Monte; however, the name didn't become popular, and instead the name of the farm, Canudos, remained in use. In Canudos, there was no private property, no upper or lower class. The city was ruled by a council of 12 "apostles", and followed a strict set of religion-inspired rules, such as the prohibition of liquor and prostitution, no civil marriage, and mandatory religious activities. Soon, more and more people abandoned the farms of the rich and turned away from the Catholic Church, migrating to Canudos. The Brazilian government, pressured by the upper class and the Church, took action. Thus began the War of Canudos.
Four attacks were required to bring down the village. In the firs three, the soldier were completely defeated with barely any casualties in the rebel's side, through the clever use of traps. On the fourth attack however, the Brazilian brought a murch larger force and heavy artillery to Canudos. Seeing that the fourth assault was taking much longer to end than the others, Anthony isolated himself to pray and fast, in an attempt to contact God and ask for divine intervetion. God did not answer, Antônio died of dysentery, Canudos fell, and more than half of the city's inhabitants were brutally killed. The army unearthed his body, beheaded it and sent the head to the governor, as proof of his death, and as a war spoil. It was exhibited in a museum until a fire in 1905 destroyed it.
As a religious fanatic, it is highly unlikely for Antônio to willingly cooperate with an unscrupulous magus seeking the Grail for selfish reasons. Rather, he will attempt to "save" the poor and miserable, using his Noble Phantasm to create a haven for them, away from the evils of society. With the Holy Grail in hands, he will likely wish for the "salvation of mankind". If he ever obtained a Grail, he would it to strengthen and enlarge his Noble Phantasm.