VA: Stephen Fu (ENG), Koki Uchiyama (JAP)

Alias: Pestilence Devil, Sickness Devil

Species: Devil

Nationality: Japanese

Age: Unknown

Gender: Male

Height: 5'11

Weight: Unknown

Eye Color: Dark

Hair Color: Black

Relatives: Death Devil (older sister), Makima (older sister), Fami (younger sister), Yoru (younger sister)

Affiliation: Four Horsemen (formerly), Public Safety Devil Hunters (sometimes)

Alignment: True Neutral

Personality

Shiku has a laxed, almost lazy like personality. Much like Fami, Shiku doesn't care if someone discovers his true identity and therefore puts little to no effort into hiding his alias. What's more is that he doesn't necessarily seem to be as outwardly malicious as his sisters, particularly Yoru.

Unlike Makima and Fami, Shiku is not interested in using Chainsaw Man for his own agendas. Believing that a wild animal is better to left all by itself to do whatever it pleases, he does not care if he eats Devils or not.

While Shiku got along very well with his older sister Death, he did not get along with Control and Yoru. He called Control a "control freak" who had weird things with putting people in leashes while calling Yoru a "spoiled brat throwing tantrums", and making fun of her bird-like Devil form and calling it ugly, which still irritated the War Devil to this day. As for Fami, Shiku do have some form of bond toward her, as he still called her his little sister.

Befitting his title as the Pestilence Devil, Shiku mostly appears as a sickly young man. He often stays at streets where the homeless or wild animals are because its filled with diseases, which pleases him a lot. Not to mention seeing people getting sick makes him very happy, almost having some form of strange pleasure from them. He also often injects himself with drugs or eat rotten food or from the garbage because he claims that getting sick makes him stronger. While he does feel irritated that humans keep coming up with new medicines and treatments for his sickness, he do have some respect for them trying.

Biography

Shiku is the Pestilence Devil (病気の悪魔, Byōki no Akuma) who embodies humanity's fear of diseases and getting sick. He was the original member of the Four Horsemen alongside his three sisters: The Death Devil, Yoru the War Devil, and Fami the Famine Devil.

Initially, he was believed to be kicked out from the Horsemen by Makima. However, the truth was that he willingly left the Horsemen because of his sisters' obsession toward Chainsaw Man and their constant battle against him alongside the Weapon Devils, though he was very fond of the Weapons, especially Gun, Bomb, Crossbow, and Longsword.

At some point he arrived on Earth as well, enjoying the people getting sick from him.

During this time, he learned that Chainsaw Devil was on Earth, where he became a hybrid with a boy named Denji. However, he simply let him be as he didn't cared about him.

When Makima's powers led to many people that he was planning to get sick were already killed, out of irritation, he saved many of Denji and his friends in hopes of one day he can get them sick. He later used his powers to get Makima sick, before allowing Denji to kill her. He expressed his own shame at how all this time she was such a bore, before leaving. 

Later, Shiku asks Denji if he has any leftovers of Makima's body that he eat, hoping to get sick from it.

Powers

Immense Strength: Much like his sisters, Shiku possesses incredible superhuman strength, allowing him to fight everyone on equal terms.

Pestilence Manipulation: As he embodies the humans' fear of diseases and getting sick, Shiku has the ability to induce various diseases and illnesses toward people. He can cause people to become sick around him, as being generally around him will cause people to suffer from vomiting, coughing, fever, rashes, and nosebleeds. He can even create viruses that have various effects, such as creating flesh-eating viruses that can melt people from inside out. Some of the diseases like AIDS which disappeared due to him leaving the Four Horsemen, can be used as well. Even his sisters aren't immune to his powers, as they can be severely weakened by his diseases.

Drug Addiction Inducement: Because drug addiction also counts as getting sick, Shiku is also able to cause symptoms of drug addiction around him. Not only that, he can cause people to overdose on certain drugs without them actually taking them. 

Sickness Empowerment: Whenever people gets sick, the stronger Shiku becomes.

Quotes

"Even after all this time... You're still boring as ever.... Big sister." (to Makima)

"If you wanna go wild, Chainsaw Man, I really don't care. After all, that's what wild animals do, right?"

"You can't get sick when you're dead."

"Leave me some too. Raw meats that get humans stomach aches are my favorite."