- "Life is cruel - the only way you can get through it is by being cruel right back."
- —Kasuto Cavanaugh, Pulling the Strings
Kasuto Cavanaugh (カーバーナオ 可巣戸, Ka-ba-nao Kasuto) is a major character in the series.
Kasuto is a cold young man, not going out of his way to try and be friendly to anyone. His view on the world is black and white: there are good people, and there are bad people. And 95% of the time, everyone is a bad person. This belief extends to himself, as he believes he, too, is a bad person, following the logic "In order to survive in a corrupt world, one must be corrupt as well." Because he is incredibly bitter about the corruption he witnessed as a child, he is also almost always angry. For the most part, his rage is set at a low boiling point, but because of this, has a tendency to explode in anger at the slightest provocation. While quick to threaten violence, he usually attempts to reel back actually jumping into violence unless he feels the occasion truly calls for it. At the very least, he does not attempt to pick fights during school hours, belying intelligence behind what can be considered a brutish exterior.
Kasuto has a particular hatred for those that believe in the "good" of the world, thinking them idiotic. Believing the true nature of humanity to be negative and oppressive, he sees his gang as proof that his line of thinking is right, and, thusly, takes pride in it. He treats his rag tag "gang" more like a business, and as the "president" of his "company" does not tolerate insubordination. Kas has very few rules for his gang, and the few he does have, he expect them to be kept. The first of which is to leave the student council alone, as they regrettably do have more power than they do; the second rule is to try and think before one acts, as if you do something really stupid and get in trouble for it, you deserved it. For the most part, though, he lets delinquents do as they please, as long as he gets a cut in where money is concerned, and should they go against his rules... well, they'll wish the student council had caught them.
The only times that Kasuto does not seem to be constantly seething in anger are actually when he's reading manga or drawing. It seems to be the way he escapes from his constant spewing of volcanic hatred is by escaping into drawing and reading his manga. He's quite protective of his sketches, however, and doesn't let anyone see them. This is because despite all his best efforts, everything he draws is cute, and doesn't fit his tough guy image. He regularly threatens to blind anyone that even gets near his sketchbooks, and touching his sketchbooks without permission usually almost always does automatically set him into violence.
Kasuto was born to a Korean mother and an American military man. For the most part, he spent his early childhood in South Korea, growing up on the base and leading a relatively cheerful life with his parents. At around eight years old, his father received a reassignment to Okinawa, and while his mother wasn't particularly thrilled about it, the family moved. They acclimated well to their new environment, but his mother soon was diagnosed with terminal cancer. She died a few months later, leaving only Kasuto and his father. The father-son duo were quite close, with Kas even wanting follow in his father's footsteps when he was older. Unfortunately, the happy days with his father wouldn't last. When he was 12, foul play on the base lead up his father's death and a full acquittal for the killer, deeming what was to Kasuto a very obvious murder as "accident beyond anyone's control."
Kasuto was put in the custody of his uncle, moving to where his uncle worked in Tokyo. Despite his uncle and cousin trying to be there for him, it was apparent that the rowdy teen didn't want to be helped through this trying time in his life. He lashed out in classes, was frequently absent, and was a general menace enough to keep him held back a year in school. It was clear to Kasuto's uncle that he was going to quickly go from delinquent to yakuza henchmen in no time with the way the boy was acting, and his uncle had been lucky enough that Kasuto seemed to like manga. An interest in manga and drawing curbed Kasuto's delinquent tendencies, but not by much. His reputation was still awful, and he still lashed out in violence to anyone who provoked him.
When time for high school came, Kasuto's uncle went above and beyond for his nephew, allowing him to attempt the exams to Gakushoku Academy. Kasuto honestly had no care to go, but the teachers of his middle school were so condescending that he refused to let them win. He studied hard, and was able to pass the exam with flying colors out of sheer spite for those who said he couldn't do it. Scholarship obtained, his uncle couldn't have been happier for him, as moving to Inochikage City and attending Gakushoku would allow for Kasuto to get a fresh, new start. Fresh start or no, it wasn't long into his attending Gakushoku that he fell into a bad crowd. While he still kept his grades up for the classes he did attend, he had no desire to turn over a new leaf, and quickly managed to assert himself as Gakushoku's toughest delinquent and the so-called "leader" of them. He surprisingly takes the role pretty seriously and even has a "code" amongst his gang about what they can or cannot do.
- Despite being 17, Kasuto is a second year in Gakushoku Academy, due to his having been held back a year in middle school for absenteeism and being a general menace.