"Humankind cannot gain anything without first giving something in return. To obtain, something of equal value must be lost. That is alchemy's first law of Equivalent Exchange. In those days, we really believed that to be the world's one, and only truth."
― Alphonse Elric (Fullmetal Alchemist)
"All magic comes with a price!"
― Rumpelstiltskin (Once Upon a Time)
"It's a double-edged sword...The fighting technique could cost them their life."
― Brook on the Mink's Sulong Form (One Piece)
"That may be what you believe, but there are certain forces that even a Master of the Mystic Arts should not dabble in."
― The Ancient One (Marvel Cinematic Universe)
"This body, this soul, even if it falls into an endless ravine! We will exhaust this body and this soul to rise up the endless royal road! Raze, triumph, play, and shine! This is the body of a Demonic Beast! Lodged on top of my fist, is the glorious imperial authority! Dance! Bloom! Breakdown The Beast, Climb Over!"
― Sairaorg Bael (Highschool DxD)
The circumstance in which the user possesses great strength and ability at a cost. Not to be confused with Aversion.
The user possesses great skill and power, but prolonged usage of it may come at a cost. Overuse or misuse of said power may result in, among other things, insanity and physical damage to the user's body.
As a result of his usage of a magical gauntlet, Mozenrath's (Aladdin: The Animated Series) right hand was stripped of all skin and flesh, leaving the only animated bone. Furthermore, said gauntlet also drained his life force, dooming him to a premature demise.
Hayley Smith (American Dad!) was trained through Project Daycare into an unstoppable sleeper agent, but the flaw is that if she is activated for 7 days consecutively, she would malfunction and turn on her handler (her father Stan).
In the Avatar State, the Avatar (Avatar: The Last Airbender/The Legend of Korra) is at their most powerful, but should the Avatar be killed in this state, the cycle of reincarnation will be broken, and the Avatar will cease to exist.
The Telecephaloscope (Blake and Mortimer) allows one to control the target's Mega Wave, granting them superhuman strength,…
…but if received without a Mega Receiver helmet, the target will be disintegrated by the high energy.
Before managing to overcome this drawback, whenever Danny Fenton (Danny Phantom) used his Ghostly Wail it would drain his energy extremely quickly, forcing him to revert back to his human form.
The Red Sweater of Courage (Dave the Barbarian) is able to grant the wearer limitless courage at the cost of their common sense.
To restore his powers after his cells were mutated by Vandal Savage to prevent him from absorbing Yellow Solar radiation, Superman (DC Comics) was forced to use Kryptonite as Chemotherapy that gave him incredible power and eventually restored his original powers, though it also affected his healthy cells which left him terminally ill, and ultimately cost him his life.
The zombie Spider-Man (Marvel Comics) can use his own veins and arteries as makeshift webbing, but doing so causes him intense pain despite being a zombie.
Trixie (My Little Pony: Friendship is Magic) was given untold powers from the magic, Alicorn Amulet, but the more she used it, the more it corrupted her.
Miraculouses (Miraculous: Tales of Ladybug & Cat Noir) are pieces of jewelry imbued with great magic and grant those who wield them with great power. However, using the Miraculouses' special powers causes the person wearing them to only have a limited time before transforming back…
...Ladybug's Lucky Charm...
...Cat Noir's Cataclysm,...
...Rena Rogue's Mirage,...
...Queen Bee's Venom,...
…even Hawk Moth after corrupting in spite of being able to maintain his transformation longer than Ladybug and Cat Noir.
Since Copycat's (Miraculous: Tales of Ladybug & Cat Noir) powers is similar to Cat Noir's, he also has a time limit after using Cataclysm
As Antibug's (Miraculous: Tales of Ladybug & Cat Noir) powers are almost similar to Ladybug's, she only has a limit time after using Anti-Charm.
Animan's (Miraculous: Tales of Ladybug & Cat Noir) animal shapeshifting powers can tire him out when he does too often.
The Ebony Blade (Marvel Comics) shares a link with its wielder and any evil acts committed by the wielder can taint the blade.
Heavyman/Dr. Koenig (Static Shock) went through an experiment that enables him to absorb mass, however, it also developed a "hunger" to satisfy it, and the more mass he absorbs the heavier he will get that eventually led him to become immobile to his literal downfall.
Michael Morningstar (Ben 10) can absorb energy, however, this can backfire on him as it can also work in reverse when he contacts to someone he has already drained, and when he absorbs more energy his "hunger" grows with his powers as energy from normal people will not sustain Michael for long, putting him in need of larger amounts.
...but because mortals' bodies aren't meant to handle magic, his mind was warped by said powers, causing him to attack criminals and harvest their organs for transplants.
Chase Collins (The Covenant) ages every time he uses his power.
Castiel (Supernatural) became one of the most powerful beings in the universe by absorbing the souls of Purgatory...
...at the price of his vessel melting and warping of his mind.
After being branded with the Mark of Cain, Dean Winchester (Supernatural) was granted the ability to use the First Blade, but was driven to bouts of murderous rage that would kill him unless he killed something regularly...
...and when he did die, he was resurrected as a Knight of Hell class Demon.
The Equalizer/Hammurabi (Supernatural) wields the power to kill anything...
...at the cost of the same amount of damage being inflicted on the shooter.
Using his strength came at a cost that would age Griffin Grey (Arrowverse) a little bit every time. The more he exerted himself, the faster he aged, which was due to a combination of the protein in his DNA being ravaged by oxidants and his suffering from oxidative stress. This side effect had progressed so far that, while Griffin was chronologically 18, he physically progressed to his mid-30s after two years of living with his powers.
Due to its sheer size, the Colossus Titan (Attack on Titan) has the rawest strength and destructive power of all Titans, at the cost of being the most taxing on its user's stamina.
A person can gain one of the Nine Titan powers (Attack on Titan) at the cost of being subjected to the Curse of Ymir, granting them only 13 years left to live at most.
Igor Planter (Black Cat) used Tao to control and become plant-life, but he overdosed on the potion that gave him power, killing him.
Gyanza Rujike (Black Cat) used his Tao to enhance his muscles, but due to his lack of training on how to use his ki efficiently, he ended up depleting his life force from overuse and died.
Those who contract Est (Bladedance of Elementalers) are granted enormous power, but the side effect is when she slays spirits, it passes on the curses and resentment of the sprites slain by her onto her master and eventually taking the user's life in exchange.
Kokujō Tengen Myō'ō (Bleach) possesses immense physical strength due to its size, but that large size also makes it a bigger target, and any damage inflicted will be reflected on its user, Komamura. Komamura's main concept of his Bankai is to utilize its immense destructive force before the opponent can cause any harm in return.
Kokujō Tengen Myō'ō: Dangai Jōe (Bleach) grants the power of immortality and increased agility, but comes at the cost of Komamura offering his physical heart to transform into a human, which when worn off, transformed him into a wolf who only thirsted for revenge.
Genryūsai Shigekuni Yamamoto's (Bleach) Bankai, Zanka no Tachi, is immensely powerful but has the risk of destroying the entire Soul Society and Yamamoto himself if left active for too long.
In his Bankai form, Kenpachi Zaraki (Bleach) gains nigh-incomparable strength, at the cost of becoming a mindless, feral berserker whose body cannot handle its own power anymore.
Shunsui Kyōraku's (Bleach) Bankai, Katen Kyōkotsu: Karamatsu Shinjū, is very powerful, but does not discriminate between friend and foe and will affect anyone within its radius, even Shunsui himself.
Shinji Hirako's (Bleach) Bankai, Sakashima Yokoshima Happōfusagari, reverses the perception of friend and foe of anyone within its area of effect, including allies, leaving Shinji alone immune to its effects.
Rukia Kuchiki's (Bleach) Bankai, Hakka no Togame, is very powerful, but requires Rukia to slowly deactivate it and thaw at the risk of shattering, during which she is all but defenseless.
Ichigo Kurosaki (Bleach) becoming one with Zangetsu and his Inner Hollow for the Final Getsuga Tensho, which would deprive him of his Shinigami powers after.
Giriko Kutsuzawa (Bleach) can use his Time Tells No Lies to set contracts with the God of Time, but cannot undo those once they are set, and can even be affected himself by the Flames of Time if the contract is broken.
Baraggan Louisenbairn (Bleach) can use his Respira to rot anything it touches. However, since this power is absolute he can also be rotted by it should it bypass his defenses.
The Tsunayashiro Clan's hereditary Zanpakutō, Enrakyōten (Bleach) allows the wielder to utilize any Zanpakutō they have witnessed, but drains their lifespan so long as they continue to use it.
Being aligned with the Archangel Gabriel, Acqua of the Back (A Certain Magical Index) is able to suppress Misha Kreutzev angel powers by 50% after absorbing half of it's Telesma...
...however he lost all his saint powers and abilities and lays at death's doorstep.
Yū Otosaka (Charlotte) can absorb the abilities of other ability-users, however for every ability he takes, he loses some of his memory.
By drawing on their Yoki energy, Claymores (Claymore) can become more and more powerful at the risk of becoming monstrous Awakened Beings…
…as was the fate of Priscilla...
Rei (Code:Breaker) can control the seven flames of hell, at the cost of something, such as his sense of taste and one of his organs.
Bai like all Contractors, (Darker than Black) must fulfill his/her task after using their powers
Arale Norimaki (Dr. Slump) using her signature N'cha Cannon, firing a powerful beam from shouting a greeting, but it is very draining on her power reserves, repeated usage will result her ceasing to function until recharge.
In their Oozaru/Great Apes form, a Saiyan's (Dragon Ball series) power level increases tenfold, but without the proper training, they lose their sense of reason, being reduced to mindless beasts.
Tenshinhan (Dragon Ball Z) using the Kikoho to cause massively powerful strikes, but it is very draining on his life-force, and repeated usage will eventually kill him.
Through the usage of the Kaio-ken, Son Goku (Dragon Ball series) can increase his speed, strength, and senses,...
...but multiplying the intensity beyond what his body can handle will damage his body and potentially kill or cripple him.
While the Ultra Instinct transformation gives Son Goku (Dragon Ball Super) incredible power…
…its continued usage eventually caused his body to begin to break down, causing heavy bleeding…
…and intense pain.
Guldo (Dragon Ball Z) can freeze time, but it only lasts as long as he can hold his breath, and expends a lot of his energy.
Frieza's (Dragon Ball Z) 100% Full Power grants him power, but with the strain on his body, he is not able to fight at maximum capacity for long, slowly weakening.
Frieza's Golden form (Dragon Ball Super) grants vast power, but quickly expends his stamina.
When Trunks (Dragon Ball Z) uses Super Saiyan Third Grade, it grants him strength and power, but the massive muscle increase inhibits his speed.
Ultimate Shenron (Dragon Ball GT) can grant any wish without restriction, but if the Black Star Dragon Balls are not returned to the place of his last summoning within a year's time, the planet on which he was summoned will explode.
Super 17's (Dragon Ball GT) barrier allows him to absorb all energy attacks, however, the pose he makes to create it leaves him vulnerable and doesn't protect him against physical attacks.
When Ultear Milkovich (Fairy Tail) uses the ultimate arc of time magic Last Ages she can rewind time for the entire planet, but in exchange she gives up all her remaining life, completely burning out all the magic in her body and rapidly ageing her into an old woman.
Kyouka (Fairy Tail) can increase the powers of those she targets, if they are not strong enough, she turns them into small paper like figures.
Using the power provided by a concept of Ultear within distorted time, Sherria Blendy (Fairy Tail) is able to use the power of Third Origin to defeat the Time wizard Dimaria Yesta, but at the price of permanently losing the ability to use magic.
Known as an evil martial art, Practitioners of Hokuto Ryu Ken/Big Dipper Lapis Lazuli Fist (Fist of the North Star) drive the risk of going mad with blind bloodlust if they use the Matōki no Aura, a special type of Ki that grants the user inhuman powers at the cost of consuming their soul, turning them into a "demon".
Rasen (Flame of Recca) can use the Kōkai Gyoku to erase anything in existence, whether it be physical, mental, or conceptual. In exchange, it takes something of equal value from the user.
After their failed attempt at bringing their mother back to life, Edward and Alphonse Elric (Fullmetal Alchemist: Brotherhood) suffered the backlash of the "Law of Equivalent Exchange," costing Ed his right arm and left leg...
...and Al his entire body. Later at the end of the manga story line, to fully restore his brother, Ed was forced to sacrifice his ability to perform alchemy as a price.
A dangerous technique from the Ancient Martial Arts, Seidou Goei (History's Strongest Disciple Kenichi) combines the opposing ki of Sei and Dou by focusing the first inward and having the second explode outward.Due to the conflicting nature of the Sei and Dou, extensive use of this technique causes disruption inflow of ki resulting in crippling, even fatal damage.
The Ros-series Heart Hybrid Gears (Hybrid × Heart Magias Academy Ataraxia) are superior to other Heart Hybrid Gears because the use the pilots life-force to increase their abilities, meaning the pilot will die if their Hybrid count reaches zero.
Miroku's (Inuyasha) Wind Tunnel can devour everything, but it grows in size every year or from damages to the sides, eventually sucking himself in, resulting in death. Also, any poison he sucks in will injure him.
In his full-demon form, InuYasha (Inuyasha) possesses great power, but his demon blood begins to eat away at his sanity and human soul.
While using his Wind Suit technique, Wamuu (JoJo's Bizarre Adventure Part II Battle Tendency) wraps himself in a whirlwind of steam giving him the ability to reflect the sun's rays off his body, but only lasting for roughly ten seconds…
…and his Atmospheric Rift, which also uses the tubes for his Wind Suit, can gather huge amounts of air and compresses it in his lungs. However, it slowly tears his body apart given the scraping and heat caused by the quick wind compression.
While Stands (JoJo's Bizarre Adventure) can grant many advantages any damage inflicted on a Stand will be reflected on their user...
...and If the user doesn't have a fighting spirit to control the Stand it can go out of control and slowly kill the user like a disease.
When Jean Pierre Polnareff's Stand, Silver Chariot (JoJo's Bizarre Adventure Part III Stardust Crusaders) removes its armor, it increases its speed, though makes it more vulnerable to attacks.
DIO's Stand, The World (JoJo's Bizarre Adventure Part III Stardust Crusaders) can stop time but only for 5 seconds. However, in spite of his Immortality increasing its power, time would only stop for about 9 seconds.
While Josuke Higashikata's Stand, Crazy Diamond (JoJo's Bizarre Adventure Part IV: Diamond Is Unbreakable) can repair damage and heal injuries of others it cannot heal its user.
Megumin (Konosuba) has mastered the Explosion spell to the absolute exclusion of any other magic, unfortunately she can only cast it once a day as it completely drains all her magic reserves, leaving her completely helpless and immobile.
Refal (Legend of the Legendary Heroes) wields Glouvil a massive sword with immense destructive power, but in order to unleash this power he must sacrifice something of himself every time its power is used.
Darkness ÄRMs (Marchen Awakens Romance) allow the user to perform curses, but many of these ÄRMs come with risky side effects.
Unlike a true ÄRM which chooses to be partners with its user, Ghost ÄRMs (Marchen Awakens Romance) gradually eat away at their user's life energy.
After receiving critical injuries during his fight with All For One, All Might (My Hero Academia) can only use One For All for three hours straight...
...causing him to revert back to his original appearance. In addition, if he's forced to use it any longer it will strain his body, as well as shorten the time limit on his Quirk.
Denki Kaminari (My Hero Academia) possesses the quirk "Electrification", allowing him to generate electricity from his body. However, exceeding his wattage limit would short circuit his brain, leaving him temporarily brain dead for an hour.
Mina (My Hero Academia) has a limit of how much acid she can produce, with her skin gradually losing its natural resistance to corrosion.
Having inherited the quirk "One For All" from All Might, Izuku Midoriya (My Hero Academia) is able to stockpile and harness power,...
...allowing him to perform physical feats unrivaled by any other quirk-user,...
...but due to a lack of control and a feeble body, the power can strain his body to the point that it would break whatever part of the body he used.
Minoru Mineta (My Hero Academia) possesses the quirk "Pop Off", allowing him to remove sticky balls from his head and place them on any surface. Should he do this too much, he eventually starts to bleed.
Rikidou Satou (My Hero Academia) possesses the quirk "Sugar Rush", which allows him to boost his strength by 5 times for every 10 grams of sugar he consumes. However, when converting sugar into strength, his cognitive functions gradually drop, making him very sleepy afterwards.
Hanta Sero (My Hero Academia) possesses the quirk "Tape", allowing him to eject strips of tape from his elbows. Overuse of this ability eventually leads to dry skin.
Tetsutetsu Tetsutetsu (My Hero Academia) possesses the quirk "Steel", allowing him to turn his body into pure steel. Use of this however causes iron fatigue, eventually weakening his form.
Thirteen (My Hero Academia) has the power to generate black holes. However, the black holes created are incredibly unstable and could cause immense damage if not regulated properly.
Shouto Todoroki (My Hero Academia) possesses the quirk "Half-Cold Half-Hot" gives the right side of his body the power to generate ice and his left side to generate fire. Overuse of one specific power could be detrimental to his body and weaken his attacks, such as the overuse of his ice powers giving him frostbite.
…the darker it is, the more savage and uncontrollable it becomes.
Ochako Uraraka (My Hero Academia) quirk "Zero Gravity", allows her to alter the gravitational weight of anyone or anything she touches. however…
…overuse causes her to feel severe nausea.
Bakugo's (My Hero Academia) quirk allows him to create explosions via the use of his sweat and ignite them, however, without his specialized bracers, repeated usage of it, particularly large explosions will result in throbbing pain to his arms and shoulders, as well as using both arms at the same time will cause their overall strength to disperse that results in weaker blasts.
Mirio's (My Hero Academia) can phase through solid matter, but is becomes incapable of seeing, hearing, or breathing when he is fully intangible and can only experience a falling sensation because he still has mass. In addition, he will also phase through his clothes, leaving him nude.
Shota Aizawa/Eraserhead (My Hero Academia) can nullify anyone's quirk by looking at them, though he needs to blink occasionally and overusing it will give him bad dry eye. His powers also don't work if anything obstructs his sight and cannot effect Mutant-type quirks.
All For One (My Hero Academia)
The Akimichi's Secret Triple Threat/Three-Colored Pills (Naruto) converts calories into chakra to make it easier to use their calorie control abilities, but are poisonous and the conversion leaves the user potentially lethally emaciated.
Being a non-Uchiha and not possessing their body, Kakashi Hatake (Naruto) suffers even more stress and fatigue from his overusing of the Sharingan than any Uchiha using it.
Upon opening all eight inner gates Might Guy (Naruto) nearly died from the side-effects with his body nearly turning to ash before Naruto saved him by stabilizing his life force, though his final technique Night Guy forced him to retire from active duty due to permanent damage to his right leg.
Mizuki (Naruto) using an experimental cursed seal that gave him animal traits with explosive power, but the strain destroyed his cells and nearly killed him.
Tsunade's (Naruto) Mitotic Regeneration/Creation Rebirth Technique shortens her natural lifespan.
In his four-tailed form and onwards, Naruto Uzumaki (Naruto) possesses great strength, but the Nine-Tailed Fox's chakra constantly destroys and regenerates his skin, shortening his life.
The more Itachi Uchiha (Naruto) uses his Mangekyō Sharingan, the more his eyesight will deteriorate…
…and accelerate his disease.
Sasuke Uchiha (Naruto) could gain an increase in chakra and power by activating the Heavens’ Curse Mark/Cursed Seal of Heaven, but extended usage caused his mind to corrode.
After receiving half of Hogoromo Ōtsutsuki's chakra, Sasuke Uchiha (Naruto) awakened the Rinnegan, allowing him to use all the Six Paths Jutsu, ability to travel through dimensions and swap places,
...however if overused each tomoe will vanish and considerably weaken him.
With the use of Izanagi and Izanami techniques, a Sharingan user (Naruto) will lose sight in their eye forever.
Mitsuki (Boruto: Naruto Next Generations) Sage Mode increases his speed tremendously, ethereal snakes appear around his body to aid in his attack range allowing him to grab and bite opponents, and use powerful jutsu's. However he can't sustain his Sage Mode for a long time as it breaks his body, to the point of deterioration, requiring several new organs to recover.
Devil Fruits (One Piece) can grant whoever consumes them a unique, life-long power, at the cost of no longer being able to swim at all.
Kuro (One Piece) can move at blinding speed, but can't see who he attacks clearly. However, his remorseless towards his crew suggests otherwise.
Overtaking the Rumble Ball (One Piece) can cause Tony Tony Chopper's Devil Fruit powers to go haywire, and even force him to expend his life force. After the timeskip he only needs one Rumble Ball to enter his Monster Point, and while he can now control himself, it still expends his life force requiring rest afterwards.
Before mastering it, Monkey D. Luffy's (One Piece) Gear Second technique would increase his strength and speed, but cause immense strain on his body and potentially shorten his lifespan…
…and Gear Third - Bone Bullon, which increases his strength,...
...however, brings about shrinking upon deactivation…
…and while using Gear Fourth - Bounceman, which greatly enhances his strength and speed similar to what both Gear Second or Gear Third individually grant...
...it also overuses his Busoshoku Haki, leaving him temporarily unable to use it for ten minutes once he reaches his limit, and also immensely taxes his body and stamina, leaving him exhausted and barely able to move after it wears off.
Despite the advantage of being able to cancel out other Devil Fruit powers via physical contact,...
...Marshall D. Teach/Blackbeard (One Piece) is more susceptible to pain than anyone else because of the gravity-based nature of the Yami Yami no Mi of drawing things in, which is the fruit's only notable weakness, even though is classified as a Logia.
The Mink's (One Piece) are granted undisputed power and fighting ability during the full moon due to the Sulong transformation, at the cost of higher brain function and their stamina. Running the risk of burning out their life force if activated for too long.
Capone Bege (One Piece) feels any damage done to him in his Big Father form and should it be destroyed, he will die.
Trafalgar D. Water Law (One Piece) can lift ships, cut or swap/switch places of people/objects, even give someone eternal youth at the cost of the users life, however...
...the Ope Ope no Mi itself shortens one lifespan if overused and depletes the user stamina to the point of causing him to collapse...
...and if the ROOM space is much bigger it might cause his lifespan to shorten faster to the point of near-death state.
Using Meteoric Burst, Boros (One-Punch Man) boosts his capabilities beyond their limits, but doing so fatigues his body and potentially shortens his lifespan.
Garo/Garou (One Punch Man) had also started to break his own limiter just like Saitama, and as a result was starting to lose his humanity and became a monster.
Saitama (One Punch Man) gained access to virtually unlimited power after breaking his natural limiter by going through a brutal training regime for three whole years, but at the cost of his hair, his ability to feel emotions (somewhat) and suffering chronic unotability in spite of his impressive strength.
While he has no issues when using his regular Caster Shells, Gene Starwind (Outlaw Star) can put his life in danger when he uses the three most powerful shells (4, 7, and 13) as they can drain his life force each time he fires one of them, to where he only uses them as a last resort.
When Pryce (Pokémon Adventures) forced Celebi to travel back in time, it adversely caused temperature dropping to absolute zero and the world completely freezing.
The Curse Series (Rising of the Shield Hero) have the highest stats among the 4 Holy Hero weapons and the strongest attacks as well. But they have many side effects and downsides with the most noticeable being they corrupted the Hero's mind and heart.
In her Iron Maiden form, Ruby Tojo (Rosario + Vampire) has great magical power, but the more she moves, the more the suit tightens around her body, causing physical damage.
In his Ghoul form, Tsukune Aono (Rosario + Vampire) possesses great vampiric powers, but at the cost of his sanity.
Yukishiro Enishi (Rurouni Kenshin) using his Frenzied Nerves to greatly amplify his five senses and reflexive speed, but it causes him to discard defense in exchange.
While Escanor (Seven Deadly Sins) can normally only sustain his "The One" form for one minute at noon, he can keep it active for longer by sacrificing his own life span in return, becoming "The Ultimate".
Kazuma (s-CRY-ed) is able to use his Shell Bullet Ultimate, but the cost of straining his right arm to the point where all feeling is lost.
Usagi Tsukino better known as Sailor Moon (Sailor Moon) with Legendary Silver Crystal tremendous power, capable of reviving an entire world from ruin but the strain of using such power often costs the user her life - as the power actually derives from the life force of the Moon dynasty, the members of which alone can actually use it.
Sailor Saturn (Sailor Moon) is the Sailor Soldier of Silence and Destruction. She uses her planetary weapon, the Silence Glaive, to utterly destroy entire worlds and planets. However doing so will kill her as well.
By using the skill「Wrath」, Wrath/Sasajima Kyouya (So I'm a Spider, So What?) can multiple all his stats by a factor of 5, but overuse and not possessing the「Heresy Nullity」skill will cause him to go berserk.
Ruki (Senyu) can create dimensional portals that can transport anyone anywhere, but doing so will cause the targets ribs to break every time.
Lina Inverse (Slayers) can cast the spell Giga Slave, which destroys anything in its way as well as bring the Lord of Nightmares into the world. However if casted improperly, The spell can destroy the entire world and be at the mercy of the Lord of Nightmares. Even if the spell is properly casted, it puts an enormous strain on her as well as turning her hair white temporarily.
When in Mover Mode, Cosmo's species (Sonic X) obtain vast power, but it causes them to expend their life force, and extensive usage is fatal.
Due to his lack of control, Hiei (Yu Yu Hakusho) burnt and almost lost his hand after using the Dragon of the Darkness Flame.
Younger Toguro (Yu Yu Hakusho) gets terribly hungry in his 100% form, requiring him to instinctively absorb souls constantly to maintain his form...
...and if he forces himself past his 100%, reaching 120%, his body will ultimately break down from strain.
Riou’s (Zatch Bell!) curse allows him to drain people’s life energy. However using the curse, puts great strain on Riou’s body, especially if used on many people.
Humans who possess a Death Note can perform the Shinigami Eye Trade (Death Note), the Shinigami who is paired with the human who has a Death Note can offer the said human their eyes, allowing them to see the name and remaining lifespan of any human-like a Shinigami would...
...but in exchange for the eyes the human's lifespan will be reduced in half, even if they forgo ownership of the Death Note they will lose the Shinigami eyes but their lifespan won't be restored.
Tokita Ohma (Kengan Ashura) using his Advance technique...
Each Crown series Gollems (In Another World with my Smartphone) have its own special ability that they offer to their master. However, their master has to pay in equal value depending on the model, such as blood, consciousness, sanity, age, or memory.
While using their Priestess Dance (Kingdom),...
...a Shiyuu swordswoman can instantly kill an opponent with incredible ease...
...however, the technique can rapidly drain a practitioner's stamina...
...and the longer a practitioner continues to use the technique, the harder the recoil effect on their body...
ADAM (BioShock) grants its user superpowers, at the cost of slowly deteriorating the users body and mind, requiring them to use more.
Azura's (Fire Emblem Fates) pendant allows her to imbue her songs and dances with magical effects, but shortens her lifespan with each use.
After injecting himself with an experimental virus to gain superhuman abilities, Albert Wesker (Resident Evil) must regularly inject himself with a special serum to keep said virus in check.
After being experimented on by Sullivan, Zephyr (Resonance of Fate) developed superhuman strength and speed, but the nature of the experiments also unhinged his mind to the point he became a mass murderer.
By drinking the Rejuvenating Sediment of the Rejuvenating Waters, Lord Genichiro (Sekiro: Shadows Die Twice) gained incredible physical resilience and regeneration powers at the cost of gradually losing his humanity.
Toothpick (Sly Cooper: Thieves in Time) gets dizzy from spinning, making him vulnerable to an attack.
Metal Sonic's V. Maximum Overdrive Attack (Sonic the Hedgehog) is unstoppably powerful, but it overloads his circuits and slows him down after a short while, and could even destroy him as backlash.
When Shadow the Hedgehog (Sonic the Hedgehog) removes his Inhibitor Rings he taps fully into his Chaos Energy giving him a massive power boost at the risk of over-exerting himself.
Vulture (Spider-Man PS4) developed terminal spinal cancer as a result of the power source of his high-tech artificial wings.
Infeliz (Valkyrie Crusade) can accurately predict fortune and future, but each time she does so, she suffers misfortune.