The central mystery of Peaky Blinders cursed vision has been solved. The show's final season has eerily centered around an ominous vision had by Tommy's daughter, Ruby, which was brought on by her having tuberculosis. An episode after Lizzie heard her chanting ''tikna mora o'beng'' and mentioning seeing a man with green eyes, Ruby told of a mysterious ''gray man'' that would come for her and Tommy. The Shelby family's Romani roots mean that Tommy didn't take to these visions lightly, as he has long believed his family to be cursed, and was visibly shaken by what they could mean for him and his family. Now, the Peaky Blinders mystery of the gray man with green eyes has seemingly uncovered itself in an unexpected way.
The identity of the ''gray man'' in Peaky Blinders has been widely speculated to be Michael Gray. Tommy's cousin swore revenge on him after the death of Polly, his mother, who he believes died as a consequence of Tommy's dangerous ambitions. This theory also aligns with Polly's prophecy to Tommy: ''there will be a war, and one of you will die.'' With this feud being significant in season 6, and Michael's last name literally being Gray, all signs seemed to point to him. However, the mysterious vision has revealed itself to be a different form.
At the end of Peaky Blinders season 6 episode 4, a doctor discloses to Tommy that he has tuberculoma in the form of a lump in his brain; a doctor with green eyes, and who wears a gray suit. He theorizes that Tommy could have contracted the illness from his daughter, and tells him that his condition is inoperable. This not only explains Tommy's visions and the seizures he's been having throughout the season, but the doctor also gives a surprising conclusion to the mystery of the ''gray man.''
Ruby specifically said that the ''gray man'' would come for her and Tommy, and they both have suffered from the same bacterial infection, just in different forms. The ''gray man'' (a doctor,) represents the illness they have both contracted, thus the ''gray man'' has taken Ruby and is coming for Tommy, who has been given a year to live. In the nature of Peaky Blinders, which has had so many iconic enemies for Tommy, the mysterious vision was thus expected to be a warning for a big Peaky Blinders season 6 villain. However, the revelation that the ''gray man'' actually takes the form of a doctor, and symbolically stands to represent unbeatable illness shows just how far the show and the characters have come in terms of tone and priorities. The doctor even states that Tommy has had many enemies but now has a new one, one inside of him that he can't fight. Season 6 has seen Tommy lean into leaving his gangster life behind, with the season being marked by a significant decline in violence, so it seems only fitting that it might not be a human nemesis to see his end, but a surprising and unyielding illness.
Tommy comments that the doctor ''looks like death'' before he has even been given a diagnosis, seemingly sealing the Peaky Blinders mystery of the ''gray man,'' as well as revealing how Tommy will die. Tommy has now come face to face with the mercilessness of mortality, and he pleads with Polly to give him the time he needs to do what he needs to do. Eerily, Polly's voice replies ''kill,'' thus time will only tell if he will continue on his moral path in his remaining time, or start to take a more ruthless approach.