Sickly Prodigy

""He's one step away from his deathbed but that doesn't mean he won't kick your ass" - Anonymous"

What you get when you combine Ill Girl / Littlest Cancer Patient with Handicapped Badass and The Gift.

This Character is extremely skilled in a fight. Often applying brains over brawn in order to win with little effort. However, when pushed too hard he may collapse in a coughing fit, or pass out post battle. He may find it hard to train, as he has to take it easy, but his talent allows him to keep up with other characters.

This may be caused by a weak immune system and frequent sicknesses that sap his strength, a single disease such as consumption or epilepsy, or might just be born with a weak body (such as a malformed heart).

This character might depend on Waif Fu and is likely to be a Fragile Speedster. Expect to him to be Weak but Skilled.

A common occurrence would be for this character to be ambushed because of his weak appearance, then fight off his attackers, only to collapse after the fight has ended

A subtrope of Handicapped Badass, if the character is old then he is likely to also be a Badass Grandpa.

Anime and Manga

 * Captain Ukitake from Bleach. Even though he's one of the most powerful Soul Reapers, his illness seems to prevent him from fighting for very long, and he appears to lapse into coughing fits at inopportune moments.
 * Subverted in The Breaker, While Shi Woon originally had such bad ki circulation that he couldn't exercise without fainting the Applied Phlebotinum fixed his health issues.
 * Kurogane Hiroto in Kurogane (not the one on the this wiki). Because of his weak body Hiroto was always the worst at sports. But when he takes up kendo his excellent eyesight allows him to avoid being hit by his opponents. At one point he faints because he's unused to the weight on the kendo armor. Waiting to see if he can strengthen his body or not.
 * Kimimaru from Naruto. He's dying from an incurable disease but has no problems wiping the floor with the protagonist and his friends. The only reason he didn't kill off the protagonist was because the strain from taking it Up to Eleven caused his disease to kill him as he was delivering the deathblow.
 * Kashitarou in Gamaran. So weak he can't swing a full katana, he uses a wakazashi instead and focuses on extreme control of his movements, in particular eliminating wasted movements.
 * Papillion from Buso Renkin, an alchemist who successfully creates several homonculi before upgrading himself in hopes of curing his Incurable Cough of Death and giving him superpowers. The getting superpowers part worked, but he was still physically frail and coughing.
 * Izumi from Fullmetal Alchemist, despite her insistence to the contrary, is a powerful alchemist and all-around badass who famously survived for a month in the frozen wastes of Briggs by raiding the military outpost there for supplies. However, she lost several of her internal organs to the Portal of Truth when she attempted human transmutation in order to resurrect her baby; she's still no less badass than before, but tends to break down coughing up blood if she exerts herself for too long.

Literature

 * Elric of Melnibone is physically frail and weak, requiring him to depend on either herbal medicine or his Life Energy draining sword Stormbringer for the strength necessary to fight. However, when he has the strength he's an excellent fighter.
 * Jem from The Infernal Devices series. He's addicted to a drug that kills him slowly but the withdrawal will kill him if he doesn't take it. So he takes as little as possible, but as the drug also gives him energy this causes him to appear very frail. Yet he is more than capable of fending for himself against the demons he frequently encounters.
 * The Dragonlance series of books has Raistlin, at least when he's human in the earlier books. Ridiculously powerful mage from a very early age, but also sickly and prone to coughing up blood.

Tabletop Games

 * Teclis in Warhammer Fantasy Battle is one of the greatest mages on the planet, but is extremely squishy, requiring potions just to stay alive.