Because you like Rory Williams in Doctor Who
Dutiful, composed, and aloof, Sun Bak is the fighting force behind her team of eight "sensates" who are telepathically linked. See them in Sense8.
Hoban Washburne shows you can be a hotshot space pilot *and* play with dinosaurs. See them in Firefly.
Winn Schott is just your friendly neighborhood superhero support system. See them in Supergirl.
Rupert Giles is a librarian on the outside, fearless evil-fighter on the inside. See them in Buffy the Vampire Slayer.
Whether it's a fire or a pit of lions, there's almost no predicament that Violet Baudelaire can't get her and her siblings out of. See them in Lemony Snicket's A Series of Unfortunate Events.
Marlin navigates through shark-infested waters, angry anglerfish, a jellyfish bloom and hungry whales to search for his son. See them in Finding Nemo.
The seasoned detectives in River Heights have got nothing on amateur sleuth Nancy Drew. See them in Nancy Drew.
Alex Danvers is a brilliant engineer tasked with alien threats, and one of those aliens is her adopted sister Supergirl. See them in Supergirl.
Though he may be blind, Chirrut Imwe sees the power of the force more than most. See them in Rogue One.
Caitlin Snow believes that burying herself in science is the best way to save the day or to mend a broken heart. See them in DC Extended Universe.
James Wilson is a compassionate doctor who willingly plays the sidekick. See them in House M.D..