Because you like Ianto Jones in Torchwood

Jenny Flint is a devoted wife and daring crime fighter, which is pretty unconventional for a Victorian maid. See them in Doctor Who.

This power-hungry Time Lord calls himself the "master of all." Bonus: he has 13 lives. See them in Doctor Who.

A dedicated hedonist, Jack Harkness appreciates raunchy stories, stiff drinks, and excellent bottoms. See them in Doctor Who.

A compassionate medical student, Martha Jones has found a Doctor she can really look up to. See them in Doctor Who.

A Silurian lizard woman, Madame Vastra has a penchant for puzzles and interspecies romance. See them in Doctor Who.

Hoban Washburne shows you can be a hotshot space pilot *and* play with dinosaurs. See them in Firefly.

Ted Logan wants to party on, but if doesn't get an A+ on his history presentation, he'll flunk out and be sent to a military school in Alaska. See them in Bill & Ted's Excellent Adventure.

Donna is boisterous and spunky traveller of the TARDIS, exploring worlds beyond the simple mundane enterprises of Earth. See them in Doctor Who.

Whether it's a companion he’s failed or lingering guilt from the war, the Doctor can never truly let go of his past lives. See them in Doctor Who.

Rory Williams is a caring companion whose specialty is looking after others. See them in Doctor Who.

There's more to this sweet, caring landlady than meets the eye. See them in Sherlock.

Working as a captain in the American Expeditionary Forces and a spy for British Intelligence, Steve Trevor wants to end World War I once and for all. See them in DC Extended Universe.