Kasuka always wears a blank expression with half closed eyes, giving away little emotion. As an actor, he is known for his extraordinary skills (he was praised as "unbelievable" when he first started out). Ironically, when he is not acting, he is a quiet, reserved man who seems to be devoid of emotion and rarely talks unless necessary.
His reserved nature, according to him, is a result of growing up alongside Shizuo, who is known to be a man of little restraint.
As a child, he was the first to witness his brother's strength as Shizuo picked up a fridge, enraged because Kasuka ate his pudding. Although he shows little emotion, he seems to care deeply for his brother, despite Shizuo's destructive rage. One or two years after Shizuo graduated high school, he was the one who was originally approached by a talent scout, not Kasuka. As a result, the talent scout would have been beaten to death had Kasuka not intervened. In turn, the talent scout turned Kasuka into a model for magazines. However, he became a famous actor as an adult, and has had to spend a lot of time away from Shizuo.
Since Shizuo had a lot of trouble holding down a job thanks to his destructive tendencies, Kasuka gave him his trademark bartender suit, hoping to help him find a permanent job and settle down. Unfortunately, Shizuo was framed by Izaya Orihara for a crime he did not commit, and much to his disappointment, lost the job his brother gave him.
While they do not talk as often anymore, they still both deeply care for each other. When Kasuka came to Ikebukuro to film a TV show, Shizuo watched him from the back of the crowd because of an online post from someone claiming that he would kill Kasuka because his ex-girlfriend was a huge fan. The man approached Kasuka and was about to stab him when a signboard flew out of nowhere and knocked the man out. Kasuka was the only one who looked to see where the signboard had come from and saw his brother quickly slipping away before he was noticed. It was later revealed that Izaya had been the one who told the man where Kasuka would be, as well as the one who informed Shizuo that Kasuka would be assassinated.
Kasuka is very popular and has a lot of fans, including Izaya's sisters Mairu and Kururi. Mairu states she would even push Izaya in front of a truck for a chance to meet him. Kasuka also seems to know Shinra because of his brother.
When Kasuka was little, he and Shizuo had a fight one day over pudding. Enraged, Shizuo came close to throwing a refrigerator at Kasuka. Luckily, Shizuo's arm broke before he could throw it. Later on, Kasuka witnessed some of Shizuo's attacks. One day Shizuo asked Kasuka if he was scared of him, to which Kasuka repiled, "Not really." Back in the present, Kasuka is about to complete some filming when he catches Shizuo in the crowd. He just looks at his big brother, and he goes out to act.
Kasuka returns to Ikebukuro to begin the shooting of his next movie. After a brief dinner with his manager and an interview, Kasuka drives back to his apartment and thinks about visiting his brother before things get busy. Seconds later, he sees the serial killer Hollywood (dressed in a zombie costume) fall out of the sky in front of him out of nowhere. He examines the injured body of the aforementioned serial killer and peels off the zombie mask to reveal none other than the rising actress/singer Ruri Hijiribe.
Kasuka takes the injured superstar to his apartment and calls Shinra Kishitani to treat her wounds. Much to their surprise, Ruri's injuries heal at an astonishing rate (second only to Celty and Shizuo as Shinra puts it) and she wakes up after a couple of hours. After Shinra leaves to get better equipment she asks Kasuka why he didn't simply call an ambulance or the police. He replies that, given Ruri's circumstances, he figured it would be better for her if he didn't get the authorities involved. Upon hearing his reply, Ruri compliments Kasuka's ability to think ahead and then proceeds to slam Kasuka down on the bed she was in and holds him by the throat, asking whether or not him getting killed was a possibility.
Kasuka questions her motives for wanting to kill him saying that if it was to keep him quiet then the security cameras littered throughout the building would quickly snuff out that plan. Ruri then asks what Kasuka would say if her motives were simply to kill him and nothing more. With his usual expressionless face, he replies that he simply doesn't wish to die and that he still has loose ends to tie up. Ruri asks what those loose ends are and is visibly surprised by his response.
(Aside from not finishing his next movie) Kasuka states that his biggest regret would be keeping Ruri from crying, quoting a line from his role as Carmilla Saizou. He also states that part of the reason he took up acting was to be able to express himself as freely as everyone else, having been deprived of those opportunities thanks to his older brother. Ruri breaks down after hearing this, realizing that Kasuka is the exact opposite of her. Kasuka was something abnormal, a "monster" of sorts, who wished to become human while Ruri was a human who wished to become a monster. She thanks Kasuka after she regains her composure.
Kasuka, in turn, apologizes to Ruri for having taken extra precautions without her consent. When he had first picked her up, Kasuka noticed several individuals tailing them as they went to his apartment. In order to keep them away, Kasuka lured several reporters to his apartment to provide ample cover for him and Ruri to escape without their pursuers noticing them.
After the manager at Ruri's talent agency, Yodogiri Jinnai goes missing, Ruri switches over to Kasuka's agency and the two of them become a couple. Ruri decides to tell Kasuka about why she became Hollywood and about her past but Kasuka denies her, saying that he knew Ruri planned to kill herself once she told him everything about her. With that in mind, he states that he won't hear about it because he doesn't want Ruri to die.
Kasuka and Ruri go to Shizuo for help regarding Ruri's stalker. Shizuo initially thinks that Kasuka is asking for his blessing for Ruri and him to get married, but Kasuka simply asks Shizuo to take care of his cat while he works on sorting out the situation.
Kadota's Coma ArcEdit
Kasuka and Shizuo are arrested under false charges (for Kasuka, it was possession of illegal drugs) by a corrupt cop named Kujira. One of Kinnosuke Kuzuhara's subordinates brings him the faulty evidence which angers Kuzuhara greatly. Kuzuhara manages to break Shizuo out of Jail but they are unable to reach Kasuka who is held in a different precinct. As of the end of the arc, he is still held in jail.
Main Article: Shizuo Heiwajima
As children, Shizuo and Kasuka were very close to one another and that bond has persisted even after the two of them went their separate ways. For obvious reasons, the two of them are rarely given the chance to visit each other and even when they do it has to be discreet so as not to attract unwanted media attention. For Kasuka, Shizuo is one of the few people he can call to for help as shown in Volume 08 when he asks Shizuo to take care of his cat while he and Ruri dealt with the stalker situation. Kasuka also feels a certain amount of responsibility for Shizuo's outbursts and was always the one who would apologize for Shizuo whenever things got out of hand. Since Shizuo was always the impulsive one, Kasuka felt the need to balance it out by being the most level headed of the two of them, which is probably one of the primary reasons for his almost apathetic personality.
Shizuo has harbored a certain amount of guilt with regards to Kasuka, mostly due to the fact that, even though he never showed it, Shizuo made things a lot harder for his family due to his frequent outburst as well as the fact that he wasn't able to hold a job even after he promised Kasuka that he would. Because of this, he's always felt inferior to Kasuka in several ways and would always gets uncomfortable when people compare the two of them. The mention of his brother is one of Shizuo's triggers: when Kasuka's name or alias is brought up by others, Shizuo flies into a destructive rage.
Main Article: Kasuka and Ruri
Max Sandshelt Edit
Main Article: Max Sandshelt
Max is the branch manager of Jack O'Lantern talent agencies, which Kasuka is affiliated with.
- Kasuka has a lot of hobbies: sports, fishing, billiard, darts, horse riding, investments, collecting automobiles, going to the theater, going to the movies, painting, calligraphy, home carpentry, table magic, aikido, flying small planes, flower arrangement, etc.
- He loves cats, and owns one that is named Yuigadokusonmaru. In the game, when Shizuo sent a picture of a tiger that he defeated to Kasuka as a sign of thanks for the hot cakes he sent, the latter soon recognized it as an endangered species. His birthday is also known as 'Cat's Day'.
- He dislikes judging people based on rumors.
- His favorite foods are homemade curry, rice pudding, and dairy products.
- He dislikes chewing gum, as he doesn't know how long he should chew it before throwing it away.