Aru Akise

Aru Akise is one of the main characters from the Future Diary anime and manga.

Aru is one of Yukiteru Amano's friends and is very intelligent and dreams of being a world famous detective when he gets older. Investigating the connections between Yuki and the diary owners, Aru becomes a close ally to Yuki, but an enemy and rival to Yuno Gasai. Aru quickly grows to love Yuki and wishes for him to become God.

Appearance
Aru is a boy with white hair and reddish-pink eyes. In his first televised appearance he wears a blue jacket over a white dress shirt and black tie. He wears grey pants and black dress shoes. All of his subsequent outfits are some variation on this.

Personality
Aru is intelligent and logical. Although he was surrounded by people who had future-predicting diaries, he was able to outsmart them. He's also extremely observant, noticing small details, putting them together, and using them to his advantage. He is also very calm and somewhat reserved with his emotions.

Aru is quite social; he doesn't hesitate to befriend those who he's only known for a short amount of time, including people who previously rivaled him, which shows how understanding he is. For instance, although Yuno attempted to kill him on multiple occasions, he still tried to understand and cooperate with her until she kidnapped Yukiteru.

Although it is shown on many occasions that Aru genuinely cares about people and wants to help them, he is not above using manipulation and breaking the law to get what he wants. Throughout the series he constantly lied and concealed the truth, broke into Yuno's house, and cooperated with Minene Uryu (a known terrorist).

Abilities
Aru receives the Detective Diary which allows him to read the predictions of other Diary Holders as well as their actions. This basically renders any opposing Diary useless, as he will always know the outcome. Despite this incredible advantage which easily makes this the most powerful Future Diary in the series, it does have weaknesses. For example, if one already knows the predictions on his Diary.

Throughout most of the series, Aru relies on his great intellect to solve things. As the detective he aspires to be, Aru is quite smart and can deduce things easily with smart bits of information. For example, during the few times that Karyuudo sent his dogs on a killing spree, Aru was capable of tracking him. He also could figure out that Yuki's Random Diary worked based on his perspective, after seeing it in action only once.

Being a detective, he has strong ties with the police mostly with Masumi Nishijima; this gives him access to resources used by the police, including confidential information and also the policemen themselves, evidenced through how he could figure out Yuki was a common variable throughout multiple incidents with the Diary Holders, as well as have the police guard different places. Nishijima even seems to rely on Aru's judgment throughout the Diary Game.

Aru has proven himself to be skilled in hand-to-hand and melee combat, as he was able to overpower Yuno even though she had pinned him down with a knife to his throat. While he is mostly seen without a weapon, when it comes to fighting he does have a preference for bludgeoning weapons like tonfa or a pipe. He is roughly on par with Yuno in terms of combat skill.

Trivia

 * Aru's character theme song is "Song of A Certain Truth" by Alice Rokugen. It expresses a desire to protect a certain person from the hardships and lies of the world, and to live a peaceful life with that person forever. It also meditates on the nature of Truth, wondering what counts as the truth and whether it's better to know nothing and live in peace.
 * His given name, Aru, can mean "exist" if written with different kanji, which could be a subtle hint to Aru's true origins.
 * In Paradox, Aru's brief alteration of history allows him to create a large alliance made out of most of the diary owners - Keigo Kurusu, Reisuke Houjou, Tsubaki Kasugano, Marco Ikusaba and Ai Mikami, Kamado Ueshita being represented by Orin Miyashiro, and Yomotsu Hirasaka. He never meets Karyuudo Tsukishimaand John Bacchus, kills Takao Hiyama and fights Minene Uryu.
 * In the Japanese dub of the anime, Aru's voice is deeper than Yuki's. However, this is reversed in the English dub.
 * Aru loves Yukiteru. He kissed Yukiteru to make Yuno jealous and charge at him. When Aru tells Deus about his will, Deus tells him it was all created and planned out by him. When Aru tells Deus that he loves Yukiteru, Deus tells him it was also part of his plan.
 * Third World Aru is called an observer by Third World Murmur and Deus.
 * He was a diary apprentice in the Second World, and he used Eighth's server to use this. His diary is called the Detective Diary, which can resolve an incident, or tell the truth. Incidentally, this is the same ability he pretended to have when he faked being a diary user in episode 9.
 * In the Third World, Tsubaki has her eyes on him and is a complete stalker.
 * Aru Akise is very similar to Nagisa Kaworu from the Evangelion franchise, particularly their love for the protagonist & close relationships with them. They also both have white hair, red eyes, holy origins, and are both voiced by Akira Ishida.