Who is the character John Wick's old friend, Jimmy, and how does he fit into the John Wick universe?

Jimmy is a character in the John Wick film series, played by actor Thomas Sadoski. He first appears in the first film, John Wick, and returns in the third installment, John Wick: Chapter 3 – Parabellum.

Jimmy is introduced as a former colleague and friend of John Wick's, who now works as a police officer. He helps John out in the first film by providing him with information about his targets and warning him when other police officers are on their way. In the third film, Jimmy is seen assisting John in his fight against the High Table, the governing body of assassins.

While Jimmy is not a major character in the John Wick universe, he provides an interesting dynamic and serves as a reminder of John's past life as an assassin. His loyalty to John despite their divergent paths is also a testament to the strong bonds forged between members of the assassin community.