Karyuudo Tsukishima

Karyuudo Tsukishima (月島 狩人, Tsukishima Karyūdo) is the Tenth diary owner. A lover of dogs, Tsukishima runs a kennel home and breeds dogs, however, he has also trained them to attack and kill people. His diary is the "Breeder Diary". He is the father of Hinata Hino.

Personality
Tsukishima is a wealthy gentleman who runs Sakurami City's dog home, treating each of his dogs like a beloved family member. He is shown preparing for them expensive meals including wine, and even has them sitting at a long dining table, although it appears they are not trained in table manners. Despite this, he was still willing to train his dogs as attack animals for his purposes and sacrificed them in droves when the Survival Game began.

Tsukishima appears to care little for humans, including himself, eating cup noodles while his dogs feast. Because of his detached attitude, Tsukishima has isolated himself from his family. He is shown to have a wife, but her location during the events of the series is unknown. His daughter Hinata loves him and wishes to earn his attention and love, having often been neglected by Tsukishima, even as a young child. Tsukishima is well aware of Hinata's need for approval, considering her to be very naive and "easier to fool than a dog".

His indifference to his daughter is shown very strongly throughout the series. Instead of fighting in the Survival Game himself, he gives his diary to his daughter and convinces her to compete on his behalf, putting her in dangerous situations while he hides in his mansion and monitors the events on his supercomputer. He even goes as far as to force her to murder innocent people in an attempt to flush out another diary holder; while he promised to reverse their actions if he became god, it is implied to be a lie (outright stated in the anime). This shows him to be a greedy and selfish man with an extremely manipulative and cowardly side.

Despite his icy exterior, Tsukishima appears to show some remorse for not being a proper father to Hinata, asking her not to become a bad person like he did.

Diary & Abilities
Karyuudo's diary is The Breeder Diary, which is mostly used by his daughter Hinata. It enables the user to see the future of both Karyuudo's dogs and the people they see. It also enables the user to control the dogs directly, with Karyuudo using code names like "Alpha 1" and "Alpha 2" for specific groups.

While the Breeder Diary grants Karyuudo a powerful army of dogs, it still requires him to personally keep track of their movements; thus, he can be rendered vulnerable if he tries to control too many dogs at once. However, he bypasses this weakness by monitoring the dogs through his huge supercomputer and allowing Hinata to direct them in the field.

As a diary owner, Karyuudo trained his dogs to be murderous and vicious attack animals, giving them metal mouthpieces to enhance their bites. He also owns a large computer mainframe which he uses during his planned attack against Yukiteru Amano and his friends; as mentioned above, this appears to help him coordinate his dogs without overloading the Breeder Diary.

The Tenth's Trap
Karyuudo Tsukishima debuts with the other diary owners at Deus Ex Machina's first meeting of the Survival Game. Like the others, he decides to make the First owner, Yukiteru Amano, his target. By late May and early June, four diary owners had been killed, leaving Tsukishima quite fearful for his life. He begins to notice Aru Akise lurking about outside and informs Hinata of his presence, guessing he is a fellow diary owner. Tsukishima comes up with an idea to give Hinata power over his diary in order to expose Akise as a diary owner, as well as make his move against Yuki. During the second meeting with Deus, Tsukishima requested to give his diary to a third party, much to Deus' surprise. Keigo Kurusu, the Fourth diary owner, informs Yukiteru of this event, revealing Deus believed it was at first an excuse to get out of the game but then allowed Tsukishima's request. Tsukishima loans Hinata his diary and his attack dogs, promising Hinata that if he became God, he would go back in time and make up for neglecting her.

Having trained his dogs to attack people, Tsukishima stages a number of serial killer-like murders, creating a similar public scare like that of the Third diary owner Takao Hiyama. The dogs work on their victims was at best horrible, acting devouring parts of their victims' bodies and leaving the remains for the police to find. When Yuki starts his new term at Umesato Elementary School, Tsukishima had lent his diary to Hinata, giving her the opportunity to gain his love and approval. Upon meeting Yuki, Hinata suggests investigating the sites where her father's dogs killed people. Yuki agrees, accompanying Hinata, Mao Nonosaka, Ouji Kosaka and the Second owner Yuno Gasai to the park where they find one of the crime scenes. Hinata runs off ahead and fakes her death, using a fake arm to make it look like she has been torn apart by her attack dogs, on loan from her father.

Akise arrives, escorting Yuki, Yuno, Mao and Kosaka to a nearby building where they manage to fend off the dogs following the instructions on Yuki's diary. Afterwards, Mao reveals herself to be in league with Hinata, taking Yuki at knifepoint. Hinata enters and takes Yuki's phone, accusing Akise of being a diary owner himself. However, Akise uses a coin toss game to outwit Hinata who tries to use Yuki's diary to predict the outcome of each coin toss. However, Akise deceives Hinata and she is forced to surrender Yuki. Akise fools Yuki into believing he has a Future Diary in order to ensure victory, but Yuno attacks him and reveals the truth. Nevertheless, Akise performs a final coin toss after conspiring with Yuno to again fool her by tricking Yuki into believing he failed at the coin toss.

Yuno attacks Hinata to get Yuki's diary back, but Mao takes a blow for Hinata and is stabbed. Yuki, Yuno, Akise and Kosaka take the opportunity to flee. The enraged Hinata orders all of the dogs to chase them, and the goes outside with the wounded Mao where she regrets her actions, believing Tsukishima will never approve of her. Yuki returns with the intention to save Hinata after she promised that they could all leave as friends if she failed the coin toss game. Yuno charges in first, taking Hinata at knifepoint and threatening to kill her unless she surrender the Breeder Diary. Yuki manages to calm Yuno down by declaring to his friends that she is his girlfriend, allowing Hinata to be spared.

Hinata laments for failing her father, only for Tsukishima to speak up through a radio device on a dog, who had actually been listening in the whole time. Tsukishima apologises to Hinata for mistaking Akise for a diary owner, but reveals his role in the game is over. Hinata asks about his promise, but Tsukishima apologises again and reveals it was a lie; in the anime, he openly laughs at Hinata's naivety and his own promise. Tsukishima criticises Hinata for her naivety, but tells her not to become a bad person like he became. Clutching a family photo of himself, his wife and a young Hinata, Tsukishima informs Yuki to beware of the diary owners who act nice, but can also be deceptive.

It is revealed that Kurusu is standing behind Tsukishima, having tracked him down using his own diary. Tsukishima identifies Kurusu as one of the "nice people", and is shot in the back of the head by Kurusu, his death heard by Yuki and Hinata. Kurusu frames Yuki and Yuno for Tsukishima's death as part of his new plan to become God to save his terminally ill son. However, Masumi Nishijima eventually clears Yuki and Yuno of the charges when Minene Uryu reveals Kurusu's alliance with her.

The Final Battle
Tsukishima appears in the third parallel world created when Yuno, Muru Muru, Yuki and Minene performed a time leap two years into the past. When Tsukishima's dogs are disturbed by the explosions occurring at Sakurami Elementary School caused by the four time-travellers, he heads outside to check on his pets. However, he is surprised to find Hinata calming down the dogs. Hinata admits she has gained an attachment to the dogs, leading to a better relationship between Tsukishima and Hinata, altering their future.

In the last chapter, Tsukishima, his wife, and Hinata are seen among the supporting characters on the streets of Sakurami City, living a better life together. In the anime, Tsukishima becomes a better parent, allowing Ouji Kosaka and Aru Akise to play with his dogs. He is last seen taking Hinata, Mao, Kousaka and Akise out.

Trivia

 * Karyuudo is not actually named until after he is killed by Kurusu.
 * He and Minene Uryu are the only diary holders who were not killed by Yukiteru or Yuno.
 * His name is a nod to the Roman moon goddess Diana, his name containing the kanji for "moon" (月) and "hunting" (狩). Karyuudo has trained his dogs to hunt down opponents, just as Diana was a great hunter and used animals to hunt as well.
 * In the manga, Karyuudo's dogs wear large metal mouthpieces whilst in the anime, their teeth are shown to be fitted with serrated metal brace-like devices.
 * While speaking in standard Japanese most of the time, Karyuudo has been shown to occasionally slip into a Kansai dialect. For example, he uses おおきに (romanized as ooki ni) in the first episode, which is the Kansai equivalent to ありがとう (arigatou) in standard Japanese. He also slips into Kansai in his last conversation with his daughter before he is killed by Kurusu.
 * He and his daughter (Hinata) have different surnames; it is possible that Hinata took her mother's maiden name.
 * In the first ending of the anime where all the Diary owners are seen standing next to each other in order of their numbers, Karyuudo is shown standing left of Minene, despite him being Tenth and her being Ninth.
 * Along with Yukiteru, Karyuudo is the only Diary holder who isn't shown being killed in the opening of Future Diary Redial.