Who Is K-9? Origin, Powers and Key Facts

K-9 (Company-Licensed): K-9 was the Fourth Doctor's pet robotic dog, there are four models of K-9, Mark I stayed with Leela on Gallifrey, Mark II stayed with Romana in E-Spac

By the Pop Culture Files editorial team•Updated July 9, 2026•3 min read•✓ Fact-checked

K-9 is a Company-Licensed comic book character, with over 99 comic issue appearances. K-9 was the Fourth Doctor's pet robotic dog, there are four models of K-9, Mark I stayed with Leela on Gallifrey, Mark II stayed with Romana in E-Space and Mark III was given to Sarah Jane as a gift by the Doctor but he later blew up and was replaced by Mark IV.

Who is K-9?

K-9 first appeared in the TV episode 'The Invisible Enemy'. K-9 mark 1 was the robotic dog of Professor Marius. After defeating the alien creature known as The Nucleus the Professor gave K-9 to the Doctor as a gift. After that K-9 mark 1 travelled with the Doctor and Leela until the TV episode 'The Invasion of Time' when K-9 decided that he wanted to stay with Leela on the Doctor's home planet Gallifrey . When the Doctor left them he pulled out a box from storage. Within it was none-other than K-9 mark 2. K-9 mark 2 travelled with the Doctor and Romana and helped them gather the parts of The Key to Time, when Romana regenerated she eventually left the Doctor and K-9 went with her through warriors gate leaving the Doctor with Adric . After that the Doctor no longer travelled with K-9, but gave mark 3 as a gift to Sarah Jane .

Key facts

K-9 is of robot origin. The character is published by Company-Licensed. With 99 recorded issue appearances, K-9 ranks among the most featured characters in comics.

Frequently asked questions

Who is K-9?

K-9 was the Fourth Doctor's pet robotic dog, there are four models of K-9, Mark I stayed with Leela on Gallifrey, Mark II stayed with Romana in E-Space and Mark III was given to Sarah Jane as a gift by the Doctor but he later blew up and was replaced by Mark IV.