Buck had been in the special operations as both a seal and a ranger from 17-27 he joins the 118 firehouse after he is forced to discharge due to what the and said was severe trauma and PTSD due to being a Prisoner of war for 3 years or whatever. He didn’t think he had an issue so he signed up to be a firefighter. He is closed off and his wife died when he got home from being discharged. He has three daughters one is 12 , one is 10 and one is 5. He is also wealthy due to having a booming computer science business.