Aru Akise

Aru Akise (秋瀬 或, Akise Aru) is one of Yukiteru Amano's friends, and becomes one of the main characters of the series. Akise is very intelligent and dreams to be a world famous detective when he gets older. Investigating the connections between Yuki and the diary owners, Akise becomes a close ally to Yuki, but an enemy and rival to Yuno Gasai. Akise quickly grows to love Yuki, and wishes for him to become God. He is the main character of the spin-off manga Future Diary: Paradox, where he and Muru Muru replace Yuki and Yuno in the survival game after Muru Muru accidentally kills Yuno while Yukiteru is injured.

The End Begins
With Kamado's help, Akise speaks directly with the dying Deus, asking him if it is possible to truly resurrect people. Deus answers the it is possible to resurrect the body, but the soul can never be brought back, therefore it is impossible to bring the dead back. With this new found knowledge, Akise realizes that Yuno had been lying to Yuki and decides to warn him; however Deus stops him and reveals another truth, that Akise is in fact a creation of Deus to serve as an observer in the game, whose duty was to obtain information. Akise denies that he was just a puppet and claims he has a will of his own, to which Deus challenges him to prove it. Akise says that he investigated both Karyuudo and Yuno out of his own will, but Deus says that Karyuudo was trying to evade the game and that Yuno is the most important person in the game. Deus gives one final chance to Akise, where Akise replies that his love for Yuki is his own, but Deus claims it is fake before banishing him. However Akise manages to turn back after successfully receiving his Detective Diary from Kamado, which Akise uses as evidence of his own free will to Deus. Amused, Deus agrees to let him do whatever he wishes.

Akise, is later found by Yuki and Yuno, and Akise says that the Eighth is in a safe place. Yuno asks where is she, and Akise mockingly says that he wants to talk with Yuki and that she should leave. Angered she stabs Akise, but proves futile as he has a protective vest. Yuno tries a stun-gun but Akise uses a rubber glove. Yuki and Yuno are shocked on how it is possible since Yuki's Diary confirms his death, and Akise reveals his Diary to them that renders theirs useless. Yuno urges Yuki to go after Kamado while he fights Akise, and he does so. Akise fights Yuno and wins with the help of his Detective Diary. However, Yuno manages to outsmart his diary by stabbing herself, to which Yuno threatens Akise that if left for dead, Yuki would hate him. Confused and shocked, Akise treats her wounds and heads as soon as possible to Yuki afterwards.

Akise uses this time to try to call out to Yuki, but he cannot make contact. He finds too late and much to his horror that Yuno had by this time tricked Yuki into killing his friends and rushes to Yuki desperately. There he finds that Yuki has killed all the others in an attempt to kill Kamado.

During his last attempt to convince Yuki about abandoning Yuno as he believes Yuno will kill him to become god. Yuno arrives wounded and tells Akise to get away from Yuki, but Akise kisses Yuki provoking Yuno. He fights once more against her ready to destroy her Diary which he does, however and much to his shock, Yuno is still alive and slices his throat. Upon reading the entry on the destroyed Diary he realizes that what he destroyed was the real Yuno's Diary instead of hers, but given that the real Yuno was never a participant, it is impossible that she would have a Diary. Pondering the rules of the game and the power of the Diaries, he finally discovers Yuno's secret.

Akise, who had discovered Yuno's secret, tries to tell Yuki, but finds himself unable to speak due to his throat injury. He is then decapitated by Yuno while trying to show Yuki his diary's screen, on which he had written his discovery about Yuno.

The Final Battle
He does not appear but Yuki remembers what Akise said to him before Yuno killed him, that Yuno had in fact already won the game in another world, and performed a time leap to the past, creating another alternate world in which the events took place. Which Yuno confirms upon attacking Yuki and revealing her intentions to start the game once more.

After Yuki successfully stops Yuno and prevents the horrible events that took place before to happen again. Akise is seen in a new happier universe alongside Hinata, Mao and Kousaka.

Diary & Abilities
For most of the game Akise does not use a Diary; although he is later given an Apprentice Diary: 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 nigh on 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 what the predictions on his Diary are, one can instead perform actions that would force Akise himself to change the future instead of trying to change it oneself. Second as demonstrated by Yuno, since it reads entries of different diaries, if one has access to multiple copies of a same Diary then it IS possible to confuse The Detective Diary. It is unknown if this method would work with different Diaries given that he could read both The Yukiteru Diary and The Random Diary, unless many more diaries could led to overflow of information - although this is unknown.

For most of the series Akise relies on his great intellect to solve things. As the detective he aspires to be he's quite smart and can deduce things easily with smart bits of information. For example, during the few time that Karyuudo sent his dogs on a killing spree, Akise was capable of tracking him. He also could figure out that Yuki's Random Diary worked based on his perspective, with seemingly no information at all.

Being a detective he has strong ties with the police mostly with Masumi Nishijima; this gives him access to resources used by the police presumably information and also the policemen themselves, evidenced how he could figure out Yuki was a common under the multiple incidents with the Diary Holders, as well as have the police guard different places.

He's an expert in hand to hand combat, being able to overpower Yuno even though she had pinned him down with a knife on his throat. While he is mostly never seen with a weapon, though he does have a preference for bludgeoning weapons like tonfa or a pipe.