Akise, Aru

A classmate in Yukiteru's school, Aru Akise dreams of one day becoming the world's greatest detective. The student detective is able to correctly deduce the culprit behind the serial dog murders even before the police.

He is mistaken for being a future diary holder due to his quick wits and superior deduction abilities. An additional evidence of his supernatural intelligence is shown through few arcs, where only Akise is able to compete against Yuno's analytical, deceptive mind. His physical prowess is nothing to scoff at either as he is able to overpower and out maneuver a psychotic Yuno in two encounters.

His reason for involving himself with Yukiteru and the Diary affair is left vague at first. But as he participated in the investigation of the Diary Holders and worked with Masumi and Minene, and after revealing himself to be apart of Nishijima's plan to eliminate the 11th, Akise calls a meeting at his house and reveals his intentions of wanting Yukiteru to become god, yet stating his deep distrust of the 2nd, Yuno.

In chapter 17 of Mirai Nikki, Akise admits in secret to Yuno that he likes Yukiteru beyond friendship, leading her to panic momentarily when he purposely wraps his arm around Yukiteru's waist to aggravate her. This might be one of the reason why Yuno is so anxious and aggravated whenever Akise is appears in front of Yukiteru.

Finally, in chapter 48, Akise admits to Deus that he is in love with Yukiteru, however Deus revealed that he only made him believe he did. Akise, desperate to prove his independence from Deus' will, claims a future diary and returns, attempting to convince Yuki that Yuno is using him.

Yuno attempts to kill Akise, but his diary's power allows him to forsee her actions and guard against them.

Mirai Nikki Paradox:

He is the main character in a spin off series (Mirai Nikki Paradox) where Murumuru accidentally destroyed Yuno from existence, meaning Yukiteru is still vulnerable from the Third. So until the damage is fixed, Aru collaborates with Murumuru and together, take the place of the First and Second.

When Akise sees Yukiteru for the first time, his heart thumps, causing him to wonder out loud "Is this love?" leading to confusion on Murumuru's part. He also states that his reward for killing the Third is for Murumuru to save Yukiteru. By the end of second chapter of "Paradox," Murumuru suspects he is gay because of his strange actions around a recovering Yukiteru; refusing to leave his side because Yukiteru's just too cute, stating how he could kill all the diary users to make Yukiteru "God," and so on.