Ai Mikami

Ai Mikami is the Seventh diary owner, which is shared with her boyfriend Marco Ikusaba. Devoted to Marco, Ai and he shares the "Exchange Diary", which the couple use to keep an eye on each other at all times. They wish to become God so they can stay together for an eternity.

Personality
Ai is a beautiful, blue-haired, purple-eyed woman, and the long-time lover/wife of Marco Ikusaba. From a young age, she loved Marco after he befriended her and gave her a family after she was abandoned by her parents as a child. She is very devoted to him, and together they form a strong battle couple. Ai is implied to be a flirtacious person, since the Apprentice Diary she gained, the "Flirting Diary", involved identifying the men she would flirt with. She seems to be at peace with Marco's constant fights, actually being a skilled knife thrower. She keeps a collection of throwing knives in her jacket, and cn throw them with pinpoint accuracy. However, she only has so many and is bamboozled when Yuno Gasai is able to deflect them all.

Despite participating in the survival game, Ai and Marco have morals. Ai takes sympathy towards Tsubaki Kasugano, the Sixth diary owner, although she expresses the knowledge that sooner or later that Tsubaki would turn into an enemy if she and Orin Miyashiro had helped her with her troubles. Ai and Marco also refuse to take a life that they do not plan to, treating the wounds of Hinata Hino and Mao Nonosaka who Ai had injured with her knives.

Marco and Ai share the "Exchange Diary", which appears as two mobile phones. The diaries allow Marco and Ai to predict each other's movements, and can protect each other when in a fight. If one of the diaries is destroyed, the other owner remains alive.

History
Fourteen years ago, Ai was abandoned by her parents at the Sakurami Tower and was told to wait for them to return. By sunset, Ai realised her parents had gone and cursed the day as being the worst of her life. It was at this point that Marco approached her for the first time, having observed her for most of the day. He told her that if that day was her worst day, than the next day would be better. Marco invites Ai to come live with him in the orphanage of Kamado Ueshita, who would become the Eighth diary owner. Ai accepted.

In high school, Ai started her first year following Marco around, having grown quite attached to him. Marco objected to her following him around all the time, but he eventually relents. The two grow close, and were implied to be dating despite Marco being a street fighter. The two eventually revisited the Sakurami Tower, Ai revealing she had her own diary based around Marco, which he suggested should focus on something other than him. The two visit the tower's chapel, Ai revealing she wants to marry Marco in the chapel.

Later, Ai finds a letter requesting a meeting in an abandoned factory. Assuming Marco sent it, Ai goes to the factory only to be ambushed and sexually assaulted by three boys. Marco arrives, angrily beating the boys and kills one of them when they draw a knife. Returning to the tower, Marco nearly kills himself with the knife but is stopped by Ai, who promises to emotionally support when he is in pain. Both declare their love for one another, kissing atop of the tower.

The Sacred Eye Incident
Ai debuts early in the story alongside Orin Miyashiro, working undercover at the Omekata temple for Kamado to observe the other diary owners. The duo act as attendants for Tsubaki Kasugano, but they are by no means loyal, planting a bomb inside a futon which causes a fire in Tsubaki's confinement room. The attempt on Tsubaki's life is thwarted by Yukiteru Amano, Yuno Gasai and Keigo Kurusu.

Ai and Orin later tend to Tsubaki's wounds after her hand was chopped off by the enraged Yuno, Ai asking Tsubaki to stay still, although Tsubaki claims she has been in worse pain, hinting to her past. Ai is present when Yuki runs in and destroys Tsubaki's Future Diary. Presumably, Ai and Orin were able to escape police custody and returned to Marco and Kamado.

The Battle of Love
Marco and Ai were sent by Kamado to intercept Yuki and Yuno, unaware of Yuki's kidnapping by Yuno. Marco, Ai, and Ta-kun, one of Kamado's orphans, pass by Yuki and his friends in a convertible. Ai shows disappointment at missing the chance to meet Yuki.

Several days later, Yuki plans to paralyze Kamado's Future Diary by jamming a nearby phone communications tower to disable the Apprentice Diaries. Marco and Ai break into Ouji Kosaka's house to confront Yuki and the recent arrival of Yuno. Ai displays her knife throwing skills by wounding Hinata Hino and Mao Nonosaka, Yuki and Yuno escaping into a room through a trap door. Ai and Marco confront them, but their Apprentice Diaries are disabled when Kosaka and Aru Akise jam the tower.



However, Ai and Marco are hardly surprised, revealing that they are the Seventh diary owners. The two immediately challenge Yuki and Yuno to a fight, Ai throwing knives which Yuno blocks. Ai is gobsmacked by Yuno's remarkable aiming skills and throws all of the knives she has, Yuno blocking each one, inspired after Yuki praised her. With no other optioned, Marco and Ai resorted to their Plan B, namely to retreat. Ta-kun set the house on fire, Marco and Ai taking Hinata and Mao outside to treat them, unwilling to have innocent lives lost in their fight.

The two head back inside the burning house to confront Yuki and Yuno again. Ai and Yuno directly confront each other, Ai horrified by Yuno's concept of earning someone's love. She manages to put up a fight, but trips on a rug, leaving an opening for Yuno. Marco runs through the flames, blocking Yuno's attack and is injured, but the lovers are able to defeat Yuno, and Yuki shortly afterwards, stealing their Future Diaries and leaving.

The Sakurami Tower
Ai learns from her diary that Marco will eventually buy her an engagement ring and is thrilled that Marco will eventually propose to her, much to Marco's surprise. Marco contacts Yuno, inviting her to attempt to rescue hers and Yuki's diaries, asking her, Yuki and Kurou Amano to come to the Sakurami Tower.

Upon Yuki, Yuno and Kurou's arrival, Marco and Ai have already married. Kurou asks Marco to hand over their diaries, but Marco promptly beats Kurou before fighting Yuki again. Kurou grabs Yuki's diary and seemingly destroys it. However, Yuno quickly realises the diary destroyed was a replica, and seizes the real diaries inside Ai's bouquet. Ta-kun begins to demolish the tower, encouraging Ai and Marco to escape to the top floor where they plan to parachute their way to safety, taking Kurou with them.



Yuki and Yuno rush to the top floor, Marco and Ai arriving shortly afterwards to find Yuno alone. Yuki talks through soundspeakers, explaining he is hiding out but aiding Yuno from afar. Enraged, Marco fights Yuno and leaves her in Ai's hold, charging up to the control room to confront Yuki only to find him missing. Downstairs, Yuki reveals he was hiding in the observation room all along, and tries to take out Ai's diary with a throwing dart. Marco runs back in, telling Ai to dodge it. The dart misses Ai by inches, but allows Yuno to move, and she slashes Ai's throat with a knife.

The tower's roof collapses, trapping Yuki, Yuno and Ai beneath a layer of rubble. Ai mocks Yuki and Yuno for failing to kill Marco, who she believes will escape alone. Yuno holds her at knifepoint, but Marco shouts out, refusing to leave Ai behind and he begins lifting a piece of rubble to save Ai. Marco encourages Yuki to help out, chastising him and Yuno for their selfish actions. Marco manages to raise the rubble enough but reveals he has been impaled by a metal rod. Yuki convinces Yuno to help out, and the manage to lift the rubble and help remove Ai.

However, by the time they do, Ai has died from blood loss. Marco cradles her in his arms and gives the last parachute to Yuki and Yuno to escape. Marco dies as the tower collapses.

The Third World
Ai and Marco appear in the third parallel world created when Yuno, Muru Muru, Yuki and Minene Uryu perform a time leap two years into the past. They are seen with Kamado at her orphanage as John Balks calls her regarding the future.

Two years later, Marco and Ai are seen walking together amongst a street of people, Ai clearly pregnant.

Future Diary: Paradox
In Future Diary: Paradox, Aru Akise and Muru Muru are forced to stand in for Yuki and Yuno after Muru Muru messes up the future by killing Yuno. Akise decides to alter the game's future by saving Tsubaki from death, convincing Ai and Orin to help him by disguising Ai as Tsubaki as a distraction so he can escape with the real one. Ai is found out by Funatsu and is shown being taken away by Omekata followers. She is later seen after Funatsu is exposed, safe and sound. When Muru Muru plans to rewind the game to alter her mistakes, Ai, Marco, Orin, Tsubaki and Reisuke Houjou come to Akise's aid to stop her. Marco and Ai fight Muru Muru and the brainwashed Yuki, but Muru Muru succeeds in her task and erases Paradox's events from history.