Lui (The Final Assassin)

When Lui (Weerapap Supappaiboon), a top-tier assassin for a secret organization established to eliminate corrupt politicians untouchable by the law, decides to wash his hands of the business to live a peaceful family life, he is instead hunted down and tragically loses his wife and child. Prakasit (Oliver Beaver), the head of the organization, frames Lui's best friend, Duan, for the murders. Believing the lie, Lui kills Duan before discovering the truth. Consumed by guilt, Lui takes in and adopts Duan's son, Boy (Poonpat Attapanyapol).
With the help of Soikeeree (Pattaratida Patcharawirapong), his ex-lover and a key figure in the organization, Lui manages to escape. He goes into hiding with Kamnan Buppha (Akumsiri Suwannasuk), his late wife's best friend. Together, they raise Boy and develop a deep bond, but out of loyalty and guilt toward his deceased wife, Lui keeps their relationship strictly platonic.
Years pass, and fate leads Boy to fall in love with Knot (Sammy Cowell), Prakasit's daughter. This forces Lui to confront Prakasit once again, and the dark truth is finally revealed. Boy "avenges" his biological father by shooting at Lui with an unloaded gun, choosing forgiveness over bloodshed. Boy then fights for what is right by teaming up with Lui to take down the secret organization. Ultimately, Lui takes it upon himself to kill Prakasit, sparing Boy from having to do it so that Boy and Knot's relationship won't be ruined. With the evil finally eradicated, peace is restored to everyone's lives once again.