Kevin Klinginpill is a firefighter who was temporarily assigned by Matthew Casey to fill Ritter's spot on Engine 51 after Darren was injured on call. Six months prior to the incident, he was on Engine 77 until he was booted. He later subbed in at Firehouse 27 but was given a full-time position there after seeing some members from 51 attempt to sneak their piercing nozzle back into their engine.