Cowardly Sidekick

A Sidekick with a peculiar twist: presumably to serve as a Foil to a brave (or cocky) hero, they're so yellow that one has to wonder how the heck they ended up in the adventure business in the first place. The Cowardly Sidekick is often what happens when the Plucky Comic Relief isn't so... well, plucky. Anything but, in fact.

Often overlaps with Bumbling Sidekick. Compare The Drag Along, for which this usually wasn't his choice to begin with. Contrast Reckless Sidekick.

Anime & Manga

 * Myoga the flea in Inu Yasha. Whoever he hides with in a battle has been used as an indicator of what's the safest place to be.
 * While Chamo of Mahou Sensei Negima may be mostly useless during fights (and not all that brave during the particularly dangerous fights), he's at least a capable strategist and is willing to be as useful a possible.
 * Pop/Poppu from Dai no Daibouken starts off like this.
 * Yoki in Fullmetal Alchemist.

Comic Books

 * In Battle Pope, this role is occupied by Jesus Christ.
 * Bob, Agent of HYDRA and sidekick of Deadpool.

Film (Animated)

 * Itchy from All Dogs Go to Heaven is an example of this who (at least at the beginning of the first film) displays traces of Hypercompetent Sidekick.
 * The Swan Princess has two, Bromley and Jean-Bob.

Film (Live-Action)

 * Malak the thief in Conan the Destroyer.
 * Snails in Dungeons and Dragons.
 * The black servant in various Haunted House movies of The Thirties and The Forties. Putting aside Unfortunate Implications, one could call them sensible rather then cowardly; when they say "Feets do yo stuff!" running is usually a really good option.
 * Herman "Fergie" Ferguson in Judge Dredd, after he and the title character escape the air transport wreck together.
 * Ruby Rhod in The Fifth Element.

Live-Action TV

 * Vila Restal, the cowardly thief, in Blakes Seven.
 * Goodwin in The Immortal for the last 400 years.
 * Edward Borman in The Mercury Men.

Newspaper Comics

 * Rip Haywire has his faithful dog, talking collie TNT, who is in near-constant panic mode.

Tabletop Games

 * Magic the Gathering's Norin the Wary, quoted in several flavor texts before getting a card of his own (with an appropriate ability, of course). He's probably the game's most famous coward, and as a summonable creature he arguably qualifies as the player's sidekick.

Video Games

 * Linebeck in The Legend of Zelda Phantom Hourglass, although he gets better towards the end.
 * Globox from the Rayman series.
 * Luigi is depicted this way in the more recent Super Mario Bros games (such as Mario and Luigi), which is partially integrated from the 90's cartoons.

Web Original

 * Craig from The Allen and Craig Show.

Western Animation

 * In Rugrats, Chuckie Finster is literally scared of his own shadow. Contrast to Tommy, who is generally fearless.
 * Penfold from Danger Mouse is an iconic example.
 * Luigi in the Super Mario Bros Super Show and its sequels.
 * Arthur from The Tick. Actually explained in the pilot basically as Arthur being unable to tolerate how mundane his life was anymore; we even see him doing his work as an accountant in costume.
 * Carl Wheezer from The Adventures of Jimmy Neutron.
 * Ron from Kim Possible.
 * Antoine from Sonic Sat AM.
 * The aptly named Cringer the Battle-Cat from He Man and The Masters of The Universe.
 * Fluttershy from My Little Pony: Friendship Is Magic is known to freak out at falling leaves and her own shadow, when she doesn't have something more pressing to attend to, like scolding an angry dragon into leaving her friends alone or glaring a cockatrice into submission. "Cowardly" is perhaps not the correct word, so much as "cripplingly timid".
 * Gus from Recess.
 * Zilly from Dastardly and Muttley In Their Flying Machines.