You Leave Him Alone - Television Tropes & Idioms

This is a common Stock Phrase utilized in a work of the action genre, mostly used by someone who up to this point in the plot has been ineffectual compared to his or her highly trained or super-powered friends.

They may even have been The Load to their companions - such is their supposed uselessness in combat - but should they be the Last Man Standing when all their warrior companions have fallen to the invincible might of the Big Bad, busy giving their obligatory Hannibal Lecture and gloating at their impending doom, the Power of Love or Power of Friendship will kick in and kick it hard.

Staggering from his or her own grievous physical (and often emotional wounds), the good hearted Every Man takes a deep breath and shouts on the top of his or her breath "You leave him/her/them alone!" and gains the Heroic Resolve to righteously kick the ass of evil that dared to lay its hands on their beloved friends.

This is the turning point of a character that will can earn the respect of the other characters (not to mention the audience) often combined with Crowning Moment of Heartwarming. They may end up as the Chekhov's Gunman or at least be using a Chekhov's Skill. Tragically, this burst of heroic resolve will often not be able to compensate for their lack of pratical combat experience and/or lack of power, so this trope will also often overlap with Heroic Sacrifice.

See also Papa Wolf, Mama Bear and Beware the Nice Ones.

Examples:

Anime & Manga

Epically invoked by Kamijou Touma of To Aru Majutsu no Index as he challenges Accelerator, a bloodthirsty and invincible psychopath who can make all your blood burst out of your veins with a mere touch, to stop him from murdering yet another kind and innocent clone on his quest to godhood.
Invoked by the first time by four year old Son Gohan of Dragon Ball Z as he demolishes his uncle Raditz, stopping him from beating his father Son Goku to death.
Saten Ruiko in To Aru Kagaku no Railgun.
Mamori does this in defense of Sena all the time in Eyeshield 21 up until Sena reveals himself to be the running back of the Devil Bats.

Film — Animated

Russell in Up as he gains the Heroic Resolve to save Carl from evil biplane flying dogs.

Film — Live-Action

What Dave, an Adorkable teenager with no fighting skills whatsoever shouts to give himself the courage to defend a mugging-victim from being murdered by three thugs in Kick-Ass
Shaun in Shaun of the Dead, as his Too Dumb to Live friend is doomed by the bites of a swarm of zombies.
Ripley's ultimate Mama Bear moment in Aliens: "Get away from her, you bitch!"
The Brady Bunch Movie features the original Peter Brady, Christopher Knight, in a scene as a coach who stops two boys from thorougyly bullying the movie Peter:
Coach: Hey. Do it, and die.
"Her" instead of "him" was used by George McFly in Back to the Future, standing up to the school bully for the first time. While possessing the resolve, he seems to lack the confidence and the physical prowess, at least for a few minutes until he manages to land a solid left hook.
Not so impressive example from The Last Airbender: Katara says this line when she runs over and shoves a Fire Nation guard who had been mocking Aang. The not so impressive part comes from the fact that after she shoves him, no one does anything for about a minute, and ultimately Aang has to use his Airbending to throw the guard away when he attacks Katara.
In Galaxy Quest, Jason Nesmith says this to Big Bad Sarris when the latter is torturing the leader of the Thermians.

Live-Action TV

Subverted for laughs in Doctor Who, "Amy's Choice", when The Dream Lord threatens Amy:
Doctor: Leave her alone!
Dream Lord: Do that again. I love it when he does that. Tall, dark, hero... "Leave her alone!"
Rory: Just leave her.
Dream Lord: Yes... you're not quite so impressive.

Video Games