Name: Kobayashi Hiroyuki.

Age: 18

Gender: Male.

Height: 179 cm.

Weight: 69 kg.

Birthday: January 4

Demon Slayer Rank: Kinoe.

Appearance: Hiroyuki has a coal-like black hair, long to his neck, which always looks messy no matter how much he tries to comb it. His skin is slightly brown. And finally, his eyes have a pretty light green color, but they always look dull and are always accompained by terrible dark circles.

Outfit: Hiro uses a black haori with a white feather pattern in the bottom and the tip of the sleeves over the regular uniform of the demon slayers. In addition, Hiro wears a very long light green scarf almost all the time, if you need to find him you just have to look for a guy with a scarf whose both ends fall below his waist.

Personality: To first sight, Hiroyuki seems to be an easily irritable or always tired person, and even though the second thing is right the first one is not, actually, he's a very gentle guy who usually speak in a soft tone and smiles very often; as an attempt to compensate the muted expression on his face, although it almost always seems to cause the opposite effect. The young Kobayashi is the type of person who always searches for something to do or someone to help, his fellows constantly demands him to take breaks more often. Hiro, like any other demon slayer, feel an enormous resentment to demons due to what happened to his family and his master, but his kindness makes him subconsciously sympathize with them, not justifying their actions, but understanding that many of them didn't choose their situations.

Likes: Animals (especially birds), sweets and spring.

Dislikes: Spicy food, lies and ungratefulness.

Fear: He has an irrational fear of sleeping, or more specifically of dreaming, so he does everything possible to avoid it.

Special Abilities: Hiroyuki has a very fast recovery, much faster than ordinary demon slayers and of course than common people. Wounds and fractures that heal in weeks, in his case heal in days, giving an example a bit exaggerated. Apparently, this healing is the reason why his wounds never leave scars, and if he slept more frequently it would be even faster. Although, this fast healing is not comparable to the accelerated regeneration of the demons, after all, Hiroyuki could never grow another arm or leg if he loses one.

Breath Style: Hiroyuki uses the "Breath of the Ghost" style, a breath style derived from the breath of mist. Kageyama Hiroshi was Hiro's mentor, but before he taught him this style he learned it from his grandfather, the swordsman who created it. The techniques of the breath of the ghost consists mainly on restrain the battle spirit in order to decrease the user's presence to a point where he becomes imperceptible for the senses of his opponent. The forms of this style are four to date: 

 - First Form: "Vengeful Phantom Slash".
 - Second Form: "Haunted Sword of Resentment".
 - Third Form: "Ephemeral Silhouettes Walk".
 - Fourth Form: "Cry of the Approaching Death God".

Family: 

 - Father: Kobayashi Hiroki - deceased.
 - Mother: Kobayashi Mayumi - deceased.
 - Older Brother (7 years older): Kobayashi Hideyuki - deceased.

Background: 

 - Hiroyuki was so happy living with his parents and his brother, even in the precarious state in which they lived. His mother was a very lovely woman and his father was a very passionate man, whose frustrated dream was to have a dojo and many aprentices, but that didn't stop him from training his children in the art of swordsmanship. They both learned the basics of the basics and practiced to the point where they could no longer move, but even so, their father always demanded more of them.

 - The father of the Kobayashi family hoped that one day his children would be way stronger than him, he expected from them to become incredible swordsmen, and they always responded with a smile to his expectations. They were happy. Or that was what the little one thought. Yeah, they were being trained to surpass their father, but... That wasn't how it had to be. "Why...?" was the only thing Hiroyuki could think when he found his elder brother stepping in his father corpse, meanwhile his dear mother was bleeding to death inside the house. "I did it Hiro... I have become stronger than this piece of trash". Hideyuki had become a demon, a bloodlust demon, and Hiroyuki believed he was going to kill him aswell, but... Was that actually bad?

 - However, in that precise moment a person appeared, a demon slayer. He was very skilled, or at least skilled enough to defeat Hideyuki in his new demon form, but also too kind to have mercy on that poor young man whose great future had been taken away. "It is really going to break my heart to take such a young life, but..." Kageyama couldn't finish his sentence, because the other boy, in a desperate outburst awakened by the anger, took the edge of his sword with bare hands and stabbed the one who was his older brother.

 - In a second, in a miserable second, Hiro just realized how his entire life crumbled completely. His father and his mother killed by his elder brother, and then, with his own hands, he killed his beloved brother. What was supposed to do from now on? He just went blank, but instead, the slayer who presenced everything knew it more than clearly.

Additional Details: 

 - Nichirin Blade: Hiroyuki's nichirin blade acquired a dull-white color when he drew it for the first time, the blacksmith who forged it was a man named Tetsuhiko, who was certainly a bit disappointed to see the color his sword took, although for some reason it didn't surprised him. He said something like "That color suits you well, actually".

 - Kasugai Crow: Hiro formed a very close relationship with his crow since the beginning. He named it Yuuki, because he always stay close, even when there are demons near, sometimes even trying to help him during battle.