Giyu Tomioka

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

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

He wears the standard black Demon Hunters uniform along with a haori with two different patterns.

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

Final Selection Arc
While Kamado Tanjirou was struggling to fend off the attack from his Demon-turned sister Nezuko, Giyuu attacked the latter from behind, only for his attempt 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, Giyuu questions this statement, before swiftly removing the girl from her brother's grip.

As Tanjirou called out to his sister in alarm, Giyuu told him not to move, stating that it is his job to kill Demons like Nezuko. The swordsman then listened as Tanjirou 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, Giyuu 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 Tanjirou's pleas to the contrary. As Tanjirou continued pleading, Giyuu brought his sword up to Nezuko's throat.

When Tanjirou then prostrated himself before the swordsman, begging for his sister's life, Giyuu 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, Giyuu demanded that Tanjirou prove his dedication to protecting his sister by drawing his axe. As the youth pondered these words, Giyuu 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 Tanjirou to throw a stone at him in fury.

Giyuu blocks the stone with the hilt of his sword, avoiding another of the projectiles as Tanjirou 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, Giyuu 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 Tanjirou'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 backwards from her kick. Cursing himself, Giyuu 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. Giyuu recalled Tanjirou'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, Giyuu sheathed his sword, incapacitating the unusual Demon with a barehanded blow to the neck.

While Tanjirou and Nezuko were unconscious, Giyuu wrapped the latter in clean cloth and strapped a bamboo muzzle-like tube across her mouth. When Tanjirou 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.

Kamado Tanjirou
Giyuu 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, Giyuu 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.

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

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

Urokodaki Sakonji
Former Water Pillar and Giyuu'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. Giyuu 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 had developed one additional by himself
 * 1) First Style: Water Surface Slice (ノ り) - A single concentrated slash
 * 2) Second Style: Water Wheel (ノ) - Giyuu jumps and spins his body while slashing.
 * 3) Third Style: Dance of the Rapid Current (ノ い) - Giyuu 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) - Giyuu 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) - Giyuu 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) - Every technique that enters Giyuu's area just dies out and becomes nothing.

Trivia

 * 義勇 (Giyuu, ぎゆう) means heroism, loyalty and courage.