Aru Akise

Aru Akise is one of Yukiteru Amano's friends, and becomes one of the main characters of the series. A 14-year old boy, Akise is very intelligent and wants 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 him to become God. He is the main character of the spin-off Future Diary: Paradox where he and Muru Muru replace Yuki and Yuno in the survival game after Muru Muru accidentally kills Yuno and Yuki is injured.

Diary & Abilities
For most of the game Akise does not use a Diary, however, he's later on given The Detective Diary which allows him to read the predictions of other Diary Holders as well as their actions. This basically renders any oppossing Diary nigh useless, and rendes also most actions useless. Despite this incredible advantage that can easily make this the most powerful Diary ever seen, it does have weaknesses. For example if one already knows what the predictions on his Diary are, one can instead perform actions that 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 led to overflow of information.

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 The Tenth 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.