Katsuo Hellsing

Gentleman Blade Below Lunar Heaven Hellsing(ジェンタルマン・ブレード・ベロー・ルーナー・ヘブン・ヘルシング; Jentaruman burēdo berō rūnā hebun herushingu), nicknamed Katsuo Hellsing(勝雄ヘルシング; Katsuo herushingu), is a student at the college section of Kuoh academy and a minor antagonist in DxD: Haremonogatari, being the first one to use physical violence against the protagonists.

He and his sister are the sole survivors of the Hellsing clan of vampire-hunters, the clan which was destroyed by Dario Aim out of boredom, and is in a quest to seek revenge for it.

Appearance
Being a year older than both Lunamaria and Ryuusei, he's a tall and handsome young man of spiky bright blue hair pulled in a short ponytail, black piercing eyes and sharp face structure. It is noted by Lunamaria he's always using bandages in his fingers and arms and wears a sarashi around his dorso.

For being a student of Kuoh academy, Katsuo is always using his typical uniform of white lined shirt, black blazer and pants. When out of it, he uses the uniform for vampire-hunter which consists on bright white shirt with black details and black leather pants.

Personality
Despite showing the will to try killing Dario Aim, Katsuo is actually quite calm and easy to approach even with his typical stoic demeanor, having countless fangirls and friends around Kuoh academy and being considered the second most beloved male in Kuoh Academy. Katsuo also refuses to drag others into his own personal wars, as he rather choose to be separated from his sister Repeat Thunder Side Hellsing instead of letting her fight alongside him on his revenge quest, and tries to avoid confront Ryuusei Amano, a normal human, even when the latter tries to defend Lunamaria Aim. He seems to have forgotten how to feel hate, as he sees his quest for revenge more like a duty than an actual personal vendetta.

Katsuo doesn't like calling people by their first names, instead calling them "[Surname]-dono", and speaks in a rather old-fashioned way, refering himself with "washi"(儂), which is stereotypically used for characters of old age.

History
Born Gentleman Blade Below Lunar Heaven Hellsing, he's the first son and former heir of the 44th generation of the Hellsing clan of Vampire hunters, direct descendants of the famous vampire Hunter Abraham Van Hellsing. Being the next head of the clan, he was trained since early age by his father Rice Blade Hellsing, the 43th Head, soon revealing himself to be a prodigy of endless potential and surpassing even elder Vampire Hunters.

However, before he could inherited from his father the position as the 44th heir, Dario Aim disguised as a vampire invaded the village in which the family lived, killing everyone except the patriarch, Katsuo and his sister, burning the entire village to the ground and stealing Rice Blade's sacred gear Clocktower Vision, giving him in return an extremely powerful healing factor that turned him practically unkillable and cursing him with a flame that will never go out, all of this out of boredom. Seeing the destruction of everything and everyone who he knew and loved and forced to bury his father under a falling mountain so that his rampaging self, who lost all sanity due to the immense suffering of his now forever burning skin, wouldn't harm anyone, him and his sister parted on a quest for revenge, which lead them to Japan and Kuoh academy.

Powers & Abilities
Master Swordsman - Unlike his sister, Katsuo is a well-versed swordsman of immense skills, compared to even the likes of the Pendragon or Miyamoto Family. His abilties with the sword are so well-polished that he can cut through anything with anything, even with weapons as blunt as a baseball bat or a piece of plank. It is stated by Lunamaria that, if he continues to train himself, he could pretty much cut across the entire planet with a book.

Master Marksman - Not being his favorite form of assault, Katsuo is also a formidable ranged fighter, able to throw sharp objects with deadly precision, and even use the enviroument in his advantage, as he used Kuoh's crowded place to attack and trap Ryuusei and Lunamaria.

Killing Intent - Katsu's own presence has an extremely volatile killing intent even when he's uninterested in killing someone. Lunamaria compares his presence as a feeling of natural dread, as in, whoever crosses him will instictivelly try to avoid him like one would avoid a natural disaster.

Yawarakai-Te
Yawarakai-Te(柔らかい手?, "Tender Hands"), is a holy japanese sword forged by Muasamune, which Katsuo received from a monk after protecting him from evil spirits, becoming his signature weapon. Shaped like a regular golden Katana, with also the regular abiltiies to slay devils and other creatures of the darkness, Yawarakai-Te gives the user the power of selective cutting, as the sword will only harm who or what the user desires, leaving anything else intact. Despite being a powerful sword, Katsuo's lack of killing intentions makes Yawarakai-Te useless for anything but parrying, as he's unable to even cut through one of his enemies Lunamaria. being extremely, sharp, Katsuo uses it as a form of transportation by cutting through dimensions.

Trivia

 * The images and appearance used are from the character Kei Munakata from the Medaka Box series.
 * In a sense of comedy, Katsuo is a parody of a foreign student of extremely exquisitive name(being his real name Gentleman Blade Below Lunar Heaven Hellsing), dark past and connections with one of the protagonists.
 * He can also be interpreted as an inversion of the typical OC archetype of exquisitve name, dark past and powerful weapon.
 * Katsuo admits he already used Yawarakai-Te for cooking.
 * So far, he's the only human in Ryuusei's circle of friends.