Colonel Spencer is a passenger aboard the train bound for Sunshine Hill in the early 1800s. He is identified as a military officer, with some sources referring to his rank specifically as a captain in the army. Spencer is a key figure in the events of the story, as the bandits who hijack the train are not only after a supposed shipment of gold but also have him specifically in their sights. This makes him a primary target of the outlaws, placing him at the center of the conflict. When the train is attacked, the six female protagonists band together to defend him and the rest of the passengers, following the instructions of the gunslinger Lola. The nature of his background, personal motivations, personality traits, and any specific abilities or combat skills are not detailed. Information regarding his development throughout the story or his key relationships with the six women, beyond the fact that they protect him, is not available.