Because of his strong endurance and representing violence, Kenpachi Zaraki (Bleach) has a high tolerance to pain and ignore fatal strikes when fighting Ichigo and Nnoitra.
Nomura Fudo (Busou Shoujo Machiavellianism) has extremely strong endurance to physical pain.
Kanon Ozu (Coppelion) cannot feel pain (or anything) due to the electricity that courses through her body numbing it entirely.
Guts, The Black Swordsman (Berserk) can continue fighting despite reserving crippling injuries e.g like being stabbed through both cheeks…
…and when wearing the Berserker Armor he doesn't feel any pain whatsoever.
Due to the physical strain and abuse on his body when he used his strength as a child, Shizuo Heiwajima (Durarara!!) grown to the point he longer feels it.
As he is just a soul inhabiting a suit of armor, Alphonse Elric (Fullmetal Alchemist) cannot feel any pain.
Cyborgs such as Motoko Kusanagi (Ghost in the Shell) are able to voluntarily shut their pain receptors off.
Due to his low regard for his own life, Gintoki Sakata (Gintama) can completely ignore injuries and pain to continue fighting viciously.
Kagura (Gintama) once gave in to her Yato instincts, ignoring all injuries to fight on.
Kamui (Gintama) can easily ignore his injuries due to his Yato blood, especially if he is consumed by its instincts.
Killua Zoldyck (Hunter x Hunter) has been trained via torture since birth to have an extreme tolerance for pain, electrocution, and poisoning.
Meruem (Hunter X Hunter) possesses incredible pain tolerance, to the extent that he can rip off his own arm without batting an eye.
Due to the experiments of the first Kiznaiver project, Agata Katsuhira (Kiznaiver) can no longer feels physical pain.
After being defeated by Phantom, Candice (Marchen Awakens Romance) has found joy in pain, openly stating she loves to feel pain more than cause it.
Having been horribly tortured in the past, Chimera (Marchen Awakens Romance) has built up an unusually high tolerance for pain. Compared to her past, even the pain of walking through boiling water is something Chimera can easily ignore and even gain pleasure from.
Mana (Mermaid Flesh) took an ax strike from Masato to protect Yuta, showing no flinching from pain.
Due to his harsh physical training, Might Guy (Naruto) is extremely resistant to pain, including the excruciating effects of the Eight Inner Gate.
Like his incredible strength and willpower, Monkey D. Luffy (One Piece) demonstrates an impressive tolerance towards unimaginable levels of pain, like when he punched through Krieg's Needle Cloak...
...withstood Arlong biting
and almost ripping it off his arm...
...take Sanji's Diable Jambe enhanced beating to the face without flinching...
Roronoa Zoro (One Piece) possesses incredible endurance to pain, able to withstand being stabbed in the chest, being crushed underneath a building and even taking on all of Monkey D. Luffy's pain and fatigue.
Due to his immense durability, Vinsmoke Sanji (One Piece) is tenacious enough to survive powerful attacks from the strongest of enemies…
…like taking a full-face thunder strike from Enel in the form of his most powerful technique, El Thor...
…withstand a brutal beating from Absalom's modified body…
…and even in his childhood, he could withstand being brutally bullied by his three superhumanly strong older and younger brothers.
Being a zombie, Oars. Sr (One Piece) cannot feel pain as his pain receptors are no longer functioning.
Having become a completely mindless cyborg, Bartholomew Kuma (One Piece) can no longer feel pain.
Edward Newgate/Whitebeard (One Piece) was able to endure having half his face burned off and a hole punched through his chest and continue fighting with no less might.
Hody Jones (One Piece) overdosed on Energy Steroids, causing insanity that overrode pain.
Hajrudin (One Piece) can withstand tremendous physical pain such as the brutal fractures of his arm, leg, and could still smash Machvise into the highest Heavens.
After years of training, Saitama (One Punch Man), who was able to suppress his pain even before he became a hero, has rendered himself unable to feel almost any pain.
Due in part to a charm placed on her, Kahlua Shuzen (Rosario + Vampire) is able to neutralize her ability to feel pain; however, this also works against her, as she has no way of knowing how much damage her body takes until it's too late.
Yukishiro Enishi (Rurouni Kenshin) has mastered mind over body, not feeling the negative effects of pain if his body does not recognize it.
Krul Tepes (Seraph of the End) was exposed to direct sunlight without a UV-protective armband for ten days till she lo longer feel it's pain.
After enduring brutal torture for ten days straight, Ken Kaneki (Tokyo Ghoul) has built up such a high pain threshold that he barely reacts to such things...
...like having his leg broken in multiple places
Checkmate (Ultimate Muscle) was put through intense training as a child to render himself unable to feel pain.
Gatasubal (Yu Yu Hakusho) does not feel pain due to its creator made it so.
Having cut off his analeptic chemicals, Minoru Kamiya (Yu Yu Hakusho) prevents himself from feeling pain.
Even after being impaled by Ou Hon's Dragon Talon, Gyou' Un (Kingdom)...
...completely ignored the wound while striking him down.
Due to his knowledge of the human body's 708 Keiraku Hikō/Hidden Points, Kenshiro (Fist of the North Star) can withstand and tolerate almost any kind of damage or wounds...
...like taking Shin's hit
...walk through fire without flinching...
With her knowledge of pressure points, Vivian Wong (Yugi Oh) can alleviate Solomon Muto of his low back pain.