John Watson

After meeting Vivian Norbury and having a tense conversation, it became clear that Vivian envied the operatives of one of the teams Mary had once been a part of and always wanted to be one of them. As the conversation progressed, it became clear that Vivian was willing to go to any lengths to protect her secrets, so she shot Sherlock with the intention of killing him to keep him from revealing anything. Mary pushed him away and took the bullet, but John had already arrived. He immediately rushed to his wife's side, trying to save her, but it was no use, and Mary died in John's arms. Realizing this, John furiously began yelling at Sherlock for breaking his promise to protect Mary at all costs. Sherlock himself was shocked that this had happened, not understanding why Mary had done it.
Later, after Mary's funeral, Sherlock comes to John's house to talk, but Molly comes out of the house with John's daughter Rosie in her arms, telling Sherlock that John is ready to accept help from anyone, but not from Sherlock, after which Sherlock silently leaves and Molly with Rosie in her arms comes back into the house, since then Sherlock's life has gone downhill, and John's life has completely turned upside down, although he tries to live on, at least for the sake of his daughter.