His story
According to apocryphal accounts attributed to Saint Ambrose of Milan, Sebastian enlisted in the Roman army around 283 AD in order to support Christians facing persecution, and rose to captain of the emperor's personal guard without his faith being discovered. Around 286, his leniency toward imprisoned Christians led Diocletian to have him shot with arrows and left for dead — an episode that became the standard image of him in later art.
Tradition holds that Sebastian survived, was nursed back to health by a woman named Irene, and confronted Diocletian again, who then had him beaten to death. His body, thrown into a Roman sewer, was said to have been recovered and buried in the catacombs by a woman named Luciana.
Syncretism
In Brazilian Umbanda and Candomblé, Saint Sebastian is commonly syncretized with the Orixá Oxóssi, particularly in and around Rio de Janeiro, reflecting a devotional pairing developed within those traditions rather than a claim from Catholic doctrine itself.