Captain Shiner is a mercenary for hire and captain of the spaceship The Vertus. He wears a monocle on his left eye and has a German-sounding accent. Like his crew, he has dog-like facial features. Whilst he is generally hired by Mumm-Ra, he is not without principle and did assist in helping Lion-O, Panthro and Snarf escape a black hole.
Captain Shiner was summoned on more than one occasion to carry out Mumm-Ra's bidding, although he did help the ThunderCats escape from a black hole once. In his second appearance, he was instructed to take the three Thunderians Lynx-O, Pumyra, and Bengali to Fire Rock Mountain to be locked away near where some Thundranium is located.