Giyu Tomioka

Giyu Tomioka is a Demon Hunter and the Water Pillar of the Demon Killing Corps.

Appearance
Giyu is a tall young man with medium length, messy black hair tied back into a low ponytail and dark blue eyes.

He wears the standard black Demon Hunters uniform along with a haori with two different patterns, one red and one geometrically patterned with green, orange, and yellow. (the latter belonged to Sabito)

Personality
Giyu always wears a serious expression on his face and has a reserved personality and a strong sense of justice. He has no tolerance towards those who don't know their own limitations and throw away their lives. Despite letting Nezuko live due to Tanjiro's persistence, like most Demon Hunters he shows no hesitation when killing other demons, and has no respect towards them.

He seems to have a complex with what others think of him and is shocked when Shinobu claims he is hated by many.

He doesn't say much and has trouble interacting with others, so he usually keeps himself at a distance.

It is revealed that Giyu suffers from an inferiority complex which he developed since his participation in the Final Selection. It gets severe to the point where he contemplates abandoning his position as the Water PIllar until Tanjiro helps him realize that instead of acting on his survivor's guilt, he should cherish his life and live on for the people who sacrificed their lives for him.

History
When Giyu was young, his family was killed by demons.

When Giyu was 13 years old, he met Sabito and they were great friends due to their similar pasts and age. They both entered the Final Selection in the Wisteria Flower Mountain. However, Giyu was injured due to a demon attacking him. Luckily, Sabito saved him before heading off towards another cry for help. It appeared that Giyu fainted and after the week was over, he was accepted. As for Sabito, he was the only one who died during that selection.

Final Selection Arc
While Kamado Tanjiro was struggling to fend off the attack from his Demon-turned sister Nezuko, Giyu attacked the latter from behind, only to fail as the former moved his target out of the way. Recovering quickly, the swordsman asked the youth why he had protected the Demon and is told that it is because the creature is the youth's sister. Looking at the maddened Nezuko, Giyu questions this statement, before swiftly removing the girl from her brother's grip.

As Tanjiro called out to his sister in alarm, Giyu told him not to move, stating that it is his job to kill demons like Nezuko. The swordsman then listened as Tanjiro attempted to defend his sister and explain their current predicament, commenting afterwards that her change in demeanor is simple to explain: any open wound bathed in Demon blood causes that person to become a Demon themselves, thus increasing their overall numbers. When the youth exclaims that his sister hasn't eaten any people, Giyu reminds him of what had just transpired, shortly thereafter bluntly commenting that there is no way to cure a person once they are turned into a Demon, despite Tanjiro's pleas to the contrary. As Tanjiro continued pleading, Giyu brought his sword up to Nezuko's throat.

When Tanjiro then prostrated himself before the swordsman, begging for his sister's life, Giyu grew angry, stating that the youth has no authority over who lives or who dies, as he was too weak to protect his family, and that all of his talk about finding a cure for his sister's condition and finding his family's killer is ridiculous. Stating that neither he or the Demon Lords would have any respect for such a miserable display, Giyu demanded that Tanjiro prove his dedication to protecting his sister by drawing his axe. As the youth pondered these words, Giyu silently encouraged him to find the resolve necessary to accomplish all of the lofty goals he had placed upon himself. He then stabbed Nezuko in the chest, causing Tanjiro to throw a stone at him in fury.

Giyu blocks the stone with the hilt of his sword, avoiding another of the projectiles as Tanjiro charged at him empty-handed. Seeing the attack attempt as only a simple act of emotion, the swordsman angrily drove the hilt of his sword into his attacker's back, knocking him to the ground. Staring down at the fallen youth, Giyu wondered where his opponent's axe was. Looking up, he saw the weapon spinning towards him through the air, and narrowly dodged it. He then mused over Tanjiro's clever strategy, realizing that the youth's plan had been to take him out even though he would have perished as well.

Distracted, the swordsman was attacked by Nezuko, dodging backward from her kick. Cursing himself, Giyu watched as the girl reached for her brother, certain that she was going to devour him. To his surprise, she instead stood protectively in front of his prone body, before charging at him in rage. Giyu recalled Tanjiro's previous assertion that Nezuko wouldn't eat humans, noting that somebody a long time ago had said the same thing and had been killed regardless. He further reflected on the nature of Demons, in particular, the high amount of stamina lost during the transformation process, and what they do to alleviate the lost stamina and prevent starvation: eat humans, even those closest to them. Seeing that Nezuko was not following this example, Giyu sheathed his sword, incapacitating the unusual Demon with a barehanded blow to the neck.

While Tanjiro and Nezuko were unconscious, Giyu wrapped the latter in a clean cloth and strapped a bamboo muzzle-like tube across her mouth. When Tanjiro regained consciousness, the swordsman instructed him to visit Urokodaki Sakonji, and also to not take his sister out in the sun, before leaving swiftly. He would later send a letter to Sakonji, asking him to train Tanjirou and explaining the youth and his sister's circumstances.

Natagumo Mountain Arc
Giyu later reappears at the Ubuyashiki residence alongside Insect Pillar Shinobu Kocho, with the two ordered to travel to Natagumo Mountain to assist the lower-ranked swordsmen. Upon arriving, he kills Lower Moon Five Rui, saving Tanjiro. He later defends Nezuko from Shinobu's attack, breaking the rules of the Demon Slaying Corps. However, he stands by as Tanjiro and Nezuko are arrested following Oyakata's order.

Dimensional Infinity Fortress Arc
Following Oyakata's death, Giyu is seen with the other Pillars attacking Muzan Kibutsuji. He eventually enters Nakime's Dimensional Infinity Fortress alongside Tanjiro. The two are soon ambushed by Akaza, with Giyu quickly sent flying away by Akaza's Destructive Leg Form: Flowing Light Flash. Giyu soon returns, angry, and manifests a mark as he begins fighting Akaza, causing his speed to increase. Akaza immediately matches Giyu's new speed and eventually gains the upper hand, breaking Giyu's blade with a punch. As Akaza closes in for the final blow, his hand is cut off by Tanjiro mid-attack, saving Giyu. Giyu then reengages Akaza once more, but is eventually defeated by Akaza's End Style: Chaotic Blue Metal Afterglow, breaking through Giyu's Eleventh Style: Lull. Giyu then watches as Akaza is beheaded by Tanjiro.

After Akaza's beheaded body begins attacking Tanjiro, the injured Giyu defends Tanjiro, vowing to protect Tanjiro with his life even as he continues to take damage. After Akaza's death, Giyu falls unconscious from fatigue alongside Tanjiro.

Kamado Tanjiro
Giyu tried to save Tanjiro from Nezuko who had been turned into a demon but was shocked to see Tanjiro protecting her. After nearly getting taken down by Tanjiro he senses his potential and sends him to his master Urokodaki so he can train him to become a Demon Hunter.

While initially hostile towards them, Giyu has come to care a lot about the siblings, willing to violate the Demon Hunters' code of conduct and put his life on the line in order to protect them.

Shinobu Kochou
Giyu and Shinobu are both Pillars of the Demon Hunters. They have opposite personalities and initially seem to be at odds with each other. Giyu was shocked when she claimed he just had a grudge on her for saying the others hated him.

Later on, both he and Shinobu are visibly upset by the hostile treatment of the other Pillars towards Tanjiro and Nezuko.

Urokodaki Sakonji
The former Water Pillar and Giyu's master and the one who taught him the Breath of Water Style. He holds him on high regard and Urokodaki seems to have a lot of trust on his former student too.

Swordsmanship
Breath of Water Style (の) : Taught by Urokodaki Sakonji. The user can increase the amount of oxygen in one's blood by controlling his breathing pattern. This increases his strength and agility to equal a demon's. Giyu has learned to do full focus breaths at all times as all pillars, further increasing his base strength, speed, and stamina. While he knows all of the Breath Style techniques, he has developed one additional by himself.
 * 1) First Style: Water Surface Slice (ノ り) - A single concentrated slash
 * 2) Second Style: Water Wheel (ノ) - Giyu jumps and spins his body while slashing.
 * 3) Third Style: Dance of the Rapid Current (ノ い) - Giyu swings his blade at his opponent in a way that mimics the movement of waves on the surface of water.
 * 4) Fourth Style: Striking Tide (ノ ち)
 * 5) Fifth Style: The Merciful Rain of a Dry Day (ノ の) - A "sword strike of kindness" that kills the target with little to no pain. Used when the enemy surrenders.
 * 6) Sixth Style: Twisting Whirpool (ノ ねじれ) - Giyu fiercely twists his upper and lower body, which creates a whirlpool that cuts anything caught in it.
 * 7) Seventh Style: Piercing Rain Drop - A fast and accurate stab. The fastest Breath of Water technique.
 * 8) Eight Style: Waterfall Jar (ノ) - Giyu cuts the target vertically.
 * 9) Ninth Style: Water Splash (ノ) - Minimizes the landing time and surface needed when landing, allowing the user to move without limits. Ideal when fighting in a place with no solid foothold.
 * 10) Tenth Style: The Dragon of Change - A continuous attack that increases in power with each rotation, creating a strong slash.
 * 11) Eleventh Style: Lull (ノ) - Technique that was created by Giyu himself. Giyu engages a skill that disables and nullifies incoming attacks. However, its effectiveness is limited as fast and numerous attacks can break through.

Trivia

 * 義勇 (Giyu, ぎゆう) means heroism, loyalty, and courage.
 * His favorite food is simmered salmon with radish.
 * Giyu was ranked in 4th place as of the first character popularity poll with 2,190 votes.
 * Giyu is the only character who has their own spinoff. It’s a two part story depicting events after Giyu’s encounter with Tanjirou and Nezuko, called Giyu Tomioka Gaiden 1 and Giyu Tomioka Gaiden 2.