The user are or able to become a berserker; beings that can empty oneself of all rational restraints in battle and completely immerse oneself in combat becoming a dangerous warrior for both friend and foe. The ability allows the user to ignore fatal physical damage as if it never affected them and continue fighting with a frightening level of stamina while also being unpredictable and erratic in combat, making it hard to counter them. The rareness of this power makes-up in one's opponent being super strong as it boosts the user's adrenaline and stamina to the point they are able to wear out their opponent through sheer tenacity and ferocity alone.
In some cases, the user is able to go in a berserk form through sheer rage or when they are in imminent danger.
The ability may be temporary due to the emotional/power overload, usually self-destructive and/or with a severe backlash at the end.
May not be able to tell friend from foe while in the berserk state, and may risk accidentally hurting or even killing allies, friends or loved ones.
While a user is able to ignore the effects of injuries sustained in the berserk state, these injuries may take full effect when they come out of the state, with ugly consequences if too much damage was taken.
While this ability makes the user much more powerful and resilient, it may also make them less intelligent.
Berserk Compound (From Commonplace to Worlds Strongest); after story only
James "Logan" Howlett/Wolverine (Marvel Comics) possesses an indestructible skeleton and claw as a result of the Weapon X Program. This, along with his regenerative healing factor, turned him into a living weapon that can recover even from the brink of death.
As a "clone" of Wolverine, Laura Kinney/X-23 (Marvel Comics) possesses a variety of his abilities, most notably her indestructible claws and regenerative healing factor.
Thor (Marvel Comics) can enter a state of Warrior's Madness which decreases his ability to think clearly but increases his strength tenfold.
Raphael (Teenage Mutant Ninja Turtles) goes into a berserker rage while fighting the Foot Clan.
In his past life as Takeshi Tatsuo, the Shredder (Teenage Mutant Ninja Turtles IDW) harnessed a berserker rage that enabled him to slaughter an army of five thousand samurai by himself.
Ever since he survived the Eclipse and became the Black Swordsman, Guts (Berserk) has been a rage-driven warrior,...
...capable tearing apart even demonic beings...
...and survive punishment that would kill lesser human many times over when he goes berserk.
Kenpachi Zaraki (Bleach) is a prime example of a berserker, able to ignore fatal strikes and overcome his opponents through sheer ferocity and bloodthirst alone.
In his Bankai form, Kenpachi Zaraki (Bleach) becomes a mindless, feral berserker unable to differentiate between friend and foe and fighting without any regard for his own safety.
Fullly Transformed Hollow Ichigo (Bleach)
Saya Otonashi (Blood+) is prone to entering a berserker rage, becoming much more aggressive and violent; at its worst, she can't discern between friend and foe.
Whenever the Demon Lord of Sloth, Belphemon (Digimon), awakens from its thousand-year slumber, it goes on a bloodthirsty rampage, destroying everything it sees, until it goes back to sleep.
Belphemon X (Digimon) is overflowing with demonic power, causing its destructive urges to increase even more.
Saiyans, such as Son Goku or Vegeta (Dragon Ball series), have a born instinct to fight despite whatever ailments they may receive, showcasing their status as natural-born fighters.
Due to her suppressed frustrations, when Kale (Dragon Ball Super) transforms, she becomes a nigh-unstoppable berserker attacking anyone she can direct her anger against.
Already having immense anger issues and traumatic experiences, Broly (Dragon Ball Super) becomes a nigh-unstoppable, mindless berserker when he transforms.
Gaara (Naruto) lost control over Shukaku when Yashamaru made him believe that nobody would ever love him, causing a rampage.
In his Jinchūriki Form Version 2, Naruto Uzumaki (Naruto) is unable to distinguish between friend and foe, attacking in whatever way will enable him to defeat his target.
Jūgo (Naruto) goes into a berserk rage whenever he lets the natural energy he passively absorbs cause his body to go out of control.
Kai Watari (Nectar of Dharani) in his Berserk Mode.
If Inuyasha (InuYasha) were to ever drop Tessaiga in battle and his life is in danger his demon blood takes over sending him into a berserk, feral stage.
Before mastering and gaining control of it, Tony Tony Chopper (One Piece) would go berserk as Monster Chopper whenever he ate three Rumble Balls within a six-hour time span.
When Cavendish (One Piece) falls asleep, his sadistic alter ego, Hakuba begins rampaging, killing allies and enemies alike.
Driven by her gluttony for sweets, Charlotte Linlin/Big Mom (One Piece) becomes a dangerous berserker.
Kaido (One Piece) is a ruthless and brutal pirate captain with a bestial hunger for war and chaos.
Nizō Okada (Gintama) went completely berserk after being taken over from his fusion with Benizakura.
Kagura (Gintama) losing control of her Yato instincts, becoming a berserk fighter.
Kamui (Gintama) losing control of his Yato instincts, becoming a berserk fighter.
Knowing Demolt (Zatch Bell!) wouldn't cooperate because of his savagery, Zofis brainwashed him with his powers. But when Demolt’s bookkeeper, Roberto Vile cast the Girugadomu Barusuruk, he was freed from Zofis’ control and returned to his berserk personality.
Girufadomu Barusuruku is a forbidden spell that turns Riou (Zatch Bell!) into a giant monster, in this form Riou had no control of himself and attacks allies and enemies alike.
Whenever her partner, Lori casts the spell, Zeruku, Kolulu (Zatch Bell!) gains a fearsome transformation of which she attacks her opponents without mercy.
Allenby Beardsley (Mobile Fighter G Gundam) with the Berserker System activated by her handlers.
Issei Hyoudou (Highschool DxD) loses all control and becomes a berserker after activating Juggernaut Drive.
Irene Belserion (Fairy Tail) can enhance Alvarez soldiers to be mindless monsters with her "Berserker" spell.
Utsutsu Hasegawa (Pupa) losing control of his Pupa instincts after learning what his "sister" really is, becoming a berserk monster.
Basara Toujou (Shinmai Maou no Testament); losing control of Brynhildr temporarily awakening his demon lord blood causing him to lose control of himself granting him the strength to overpower a low-tier god, this is trumped by...
...by his full Demon Lord form, which removes the seal on his true mother's blood granting him the power to overwhelm the current Demon Lord.
Saturn (Marchen Awakens Romance) transformed into an enormous canine-like monster after his Darkness ÄRM, Finsternis was destroyed. In this form, Saturn has absolutely no restraint and mindlessly attacks everything around him.
Kahlua Shuzen (Rosario + Vampire) is an exceedingly powerful vampiress who has been charmed to be immune to pain; when under the effects of the charm, she will blindly attack her opposition and kill them without remorse.
As a Kishin, Tenmei Mikogami (Rosario + Vampire) is a nigh-unstoppable berserker when in battle, which is why he usually keeps his powers sealed.
When her seal is broken, Muru-Muru's (Mirai Nikki) appearance alters and her moves become wild and erratic.
Hibiki Tachibana (Symphogear) enters a berserk state under extreme stress when her appearance darkens to the extent of becoming jet-black with glowing red eyes and aura.
Infamous for his viciousness, Ba Nan Ji (Kingdom) became known as the Demon of Ganmon due to his passionate, rage-filled combat skills while fighting against the Xiongnu in the Gan Mon region of the State of Zhao.
Legend says that Samson (Judeo-Christianity) when fought the Philistines the Spirit of God came to him and gained godlike strength and a great fury that slaughtered one-third of a three thousand-strong army before the rest fled, with a jawbone.
Asura (Asura's Wrath) has the astounding trait of being able to immerse himself in battle despite fatal injuries and dominate his opponents through sheer tenacity and wrathful endurance.
Augus (Asura's Wrath) of the Seven Deities is a true example of a berserker due his lust for battle, his inhuman drive to fight regardless of damage, and his thrill for combat against powerful opponents.
Whenever Rick Taylor (Splatterhouse series) absorbs blood from the Corrupted, he is able to enter a Berserker form that grants him all of the powers of the Terror Mask.
Saïx (Kingdom Hearts), when he absorbs enough moonlight, is filled with a powerful berserker rage.
When using Darkness Trigger,Lola (Gunvolt Chronicle:Luminous Avenger iX) awakening her humanoid form and enhancing all EX Weapons, providing infinite weapon energy but restrict useable of EX weapon and harming Copen while not tagging a target for attack