Except for Jesse Lynch, who seems to have survived hanging, most folks who get near Mr. Black end up dead. True, he's the undertaker in Tarnation, and everyone dies eventually. But the residents of a cursed town met their fate unnaturally soon, even by local standards. Some say Black can't be killed because he's already dead. I know only one thing for sure: every man who went after him was never heard from again.
Mr. Black was the undertaker in the town of Tarnation, before all of the residents mysteriously died. He runs a gang in the (now) ghost town of Tarnation. Although his first name is not known, Sheriff Bartlett's Journal indicates that it starts with "N".
Black had a bounty of $300, and is listed as "Dead as possible" in his journal's page in Sheriff's journal.
Mr. Black becomes available as a playable character in Showdown Mode by completing the mission "The Cemetery" with an excellent rating or by purchasing the Embalming Tools from the shop at the start of the mission "Sunset Canyon". His special ability is a machine gun mounted within a coffin that he carries. Due to the weight of this setup, he moves very slowly.
Mr. Black is listed in Sheriff Bartlett's Journal on pages 160 - 161 under the Wanted - Dead or Alive section. The pages are unlocked by unlocking his Showdown Mode character via either of the methods noted above.