"I am the messenger of truth for the Lord hath anointed me with His sacred oils. He hath separated me above all and promised me and my children their rightful place in the new kingdom."
―Deacon Blackfire's sermon[src]
A self-proclaimed deacon, Joseph Blackfire had a long history of tax evasion and other federal offences, and sold people several cons until he came to believe his own lie that humanity was fickle and soon to damnation and that he alone was blessed by God Himself.

Blackfire had amassed a cult of Gotham City's homeless who accept his fanatical beliefs that the world's end was nigh and those who accepted him would be the ones to survive. He took part in human abduction and sacrifice, and believed the way to achieve immortality was to bathe in human blood.

Batman: Arkham Knight

Deacon Blackfire was the antagonist in the Most Wanted Mission, "Lamb To The Slaughter."

After Batman rescued Oracle, Jack Ryder went to investigate the Lady of Gotham for his story, but he was captured by Deacon Blackfire and his followers for sacrifice. Blackfire prepared to sacrifice Ryder, but he was interrupted by Batman. Despite Blackfire's followers attempts at defeating Batman, Batman was able to grapple to the grate gate, took down Blackfire, and rescued Ryder. Blackfire was locked up in the GCPD Lockup along with the villains that Batman defeated. Blackfire's sacrificial knife and praying book appeared in the GCPD Evidence Room in a display case.

Deacon was most likely put on trial for kidnapping and attempted murder.

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