Ai Mikami

Ai Ikusaba (美神 愛, Ikusaba Ai), (née Mikami), is one of the Seventh diary owners, which is shared with Marco Ikusaba (Ai's boyfriend/husband). Devoted to Ikusaba, Ai and Marco share the "Exchange Diary", which the couple uses to keep an eye on each other at all times. They wish to become Gods so they can be together for all eternity.

Appearance & Personality
Ai is a beautiful young woman with shoulder-length dark blue hair and purple eyes; while infiltrating the Omekata religion, she often covers her right eye with her bangs. She normally wears a light blue sleeveless jacket and white pants.

From a young age, Ai loved Marco Ikusaba after he befriended her and gave her a family after she was abandoned by her parents as a child (in the anime, she is also grateful for his efforts to prevent her from being sexually assaulted in their high school years). She is very devoted to him, and together they form a strong battle couple. Ai is implied to be a flirtatious 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, but she is extremely insecure about their relationship; even the vaguest hint of infidelity on Marco's part is enough to send her into hysterics.

Despite participating in the Survival Game, Ai shares Marco's morals regarding their role. She sympathizes with Tsubaki Kasugano despite knowing that the Sixth would eventually become 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. She also seems more levelheaded than her lover, pointing out that they should have simply broken Yukiteru Amano and Yuno Gasai's Future Diaries when they had the chance instead of leading them on and giving them an opportunity to take them back.

Diary & Abilities
Marco Ikusaba and Ai share the Exchange Diary, a pair of mobile phones that predict each other's future. Its main advantage is that Ai can predict her own future or Marco's, depending on which phone she uses; however, she generally prefers the latter method so she can protect Marco from danger. While a fearsome combination, the Exchange Diary becomes much less effective if Ai and Marco are separated; additionally, while she would survive unharmed if Marco's phone is destroyed, it would still effectively negate the advantage of her Future Diary.

Thanks to her connection with Kamado Ueshita, Ai was also granted an Apprentice Diary that she used in tandem with her Future Diary. The Flirting Diary allows her to know the identities and locations of men she intends to flirt with, allowing her to track specific individuals. However, the diary is obviously useless against anyone Ai doesn't plan to flirt with, and like all Apprentice Diaries, it relies on a strong connection with Kamado's Blog Diary to function. On the other hand, Ai can have the Flirting Diary destroyed without any ill effects to herself, and her possession of the Apprentice Diary allows her to conceal her identity as a full Survival Game participant.

Aside from her Diaries, Ai is a skilled combatant, specializing in ranged combat with throwing knives. She keeps a large collection of throwing knives in her jacket, which she can throw with incredible speed and accuracy; notably, she is left bamboozled when Yuno Gasai successfully deflects them all. It is noted in Future Diary: Mosaic that Ai is one of the "three" main reasons why the Sakurami Beauty Contest is boring, being unbeatable in the knife-throwing competition.

While she isn't a full brawler like Marco, Ai does seem to have above average close-combat skills of her own, being able to effectively pin and restrain Yuno and having reflexes fast enough to protect her Future Diary from Yukiteru Amano's darts (albeit with a last-second warning from Marco). She also seems to be knowledgeable in other things like infiltration, first aid and parachutes.

Background
Fourteen years ago, Ai's parents took her to the Sakurami Tower and told her to wait for them to return. By sunset, Ai realized her parents had abandoned her and cursed the day as being the worst of her life. It was at this point that Marco Ikusaba approached her for the first time, having observed her for most of the day. He told her that if the day had been her worst day, then the next day was guaranteed to be better. He then invited Ai to come live with him in Mother's Village, the orphanage of Kamado Ueshita. Ai accepted the offer, being moved by Marco's consideration.

(NOTE: The following events only took place in the Future Diary anime.)

Ai started her first year of high school following Marco around, having grown quite fond of him while growing up at the orphanage. Marco objected to her following him around all the time, but he eventually relents. The two grew close, and were implied to be dating despite Marco being a street fighter. They eventually revisited the Sakurami Tower, where Ai revealed that she had made a phone diary based around Marco; in response, he suggested that she should focus on something other than him. They then went to the tower's built-in chapel, where Ai admitted that she wanted to marry Marco in it someday.

Later, Ai finds a letter requesting a meeting in an abandoned factory. Assuming Marco sent it, she went to the factory, only to be ambushed and sexually assaulted by four boys; the letter was a trap set by a group of female students who were jealous of her beauty. As Ai lay on the ground in a state of shock and turmoil, she saw Marco arrive to angrily beat her assailants, even killing one of them when they drew a knife. When Marco ran off afterwards, Ai followed him to the top of Sakurami Tower, finding him about to commit suicide out of shame for failing to protect her. She prevented him from killing himself and promised to be there for him no matter what either of them went through; they then declared their love for each other and shared a kiss.

The Cult of The Sixth
Ai did not attend the gathering of Future Diary Holders when Deus Ex Machina officially announced the Survival Game, instead allowing Marco to represent both of them. She makes her proper debut alongside Orin Miyashiro, working undercover at the Omekata temple on behalf of Kamado to observe the other diary owners. The duo acted 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 was 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 to have been in worse pain. Ai continued to watch from the sidelines as Tsubaki ordered Yuno to be gang-raped, only to be thwarted when Yukiteru intervenes and destroys Tsubaki's Future Diary. Presumably, Ai and Orin were able to escape police custody and returned to the Mother's Village orphanage.

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

Several days later, Yukiteru plans to jam a nearby phone communications tower to break the Apprentice Diaries' connection to Kamado's Blog Diary. Marco and Ai break into Ouji Kosaka's house to confront Yukiteru and the recently arrived of Yuno. Ai displays her knife throwing skills by wounding Hinata Hino and Mao Nonosaka, Yukiteru 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 Yukiteru and Yuno to a fight, with Ai's first knife throw being deflected by Yuno. Unimpressed by the apparent fluke, Ai threw two knives at once, but Yuno deflected them both as she swelled with joy over Yukiteru praising her skill. Increasingly bewildered by her attacks' failure, Ai threw several more knives at blinding speed, but the lovestruck Yuno blocked them all with ease. With her knives expended, Ai joined Marco in their backup plan; retreating through a trapdoor seconds before Yuno could slash them with her knife. When Ta-kun set the house on fire, Marco and Ai took Hinata and Mao outside to treat their wounds, unwilling to have innocent lives lost in their fight.

Once the students were safely bandaged, the Sevenths went back inside the burning house to confront Yukiteru and Yuno again. Ai and Yuno directly confront each other, with Ai being 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 Yukiteru shortly afterward, stealing their Future Diaries and leaving.

In their downtime following their victory over the First and Second, Ai discovered a prediction in the Exchange Diary claiming that Marco will receive a gift from another woman while having a pleasant conversation with her. Torn between horror, heartbreak, and utter hysteria, she tearfully confronted Marco with his apparent affair...only to read ahead and discover that he was buying her an engagement ring. When Marco sheepishly confirmed that he had been thinking about proposing for a while, Ai ecstatically hugged him. Marco later contacted Yuno, inviting her to attempt to rescue hers and Yukiteru's diaries, asking her, Yukiteru and Kurou Amano to come to the Sakurami Tower.

When Yukiteru, Yuno and Kurou arrive, they discover that Marco and Ai have exchanged vows in the tower's chapel, finally making them husband and wife. Kurou asks Marco to hand over their diaries, but Marco promptly beats Kurou before fighting Yukiteru again. In the confusion, Kurou grabs Yukiteru's diary and seemingly destroys it. However, Yuno quickly realizes 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.

Yukiteru and Yuno rush to the top floor, Marco and Ai arriving shortly afterward to find Yuno alone. Yukiteru talks through loudspeakers, explaining he is hiding out but aiding Yuno from afar. Enraged, Marco defeats Yuno and leaves Ai to hold her down while he confronts the cowardly First in the control room. However, Yukiteru reveals that he was hiding in the observation room all along; with Marco briefly out of the way, he reveals himself to Ai and throws a dart at her diary. With a desperate warning from a returning Marco, Ai is able to narrowly dodge Yukiteru's dart; unfortunately, this frees Yuno enough to slash Ai's throat with a knife.

The tower's roof collapses, trapping Yukiteru, Yuno and Ai beneath a layer of rubble. Despite her fatal wound, Ai mocks Yukiteru and Yuno for failing to kill Marco, who she believes will escape alone and continue the Survival Game. Yuno holds her at knifepoint, prepared to finish her off, but Marco shouts out to her as he begins lifting a piece of rubble, refusing to leave Ai behind. Marco encourages Yukiteru to help out, chastising him and Yuno for their selfish actions.

Acknowledging Marco's point, Yukiteru convinces Yuno to help him move the rubble from the other side, managing to help Marco remove Ai from the debris; however, by the time they do, Ai has died from blood loss. Tearfully cradling her in his arms, Marco gives the last parachute to Yukiteru and Yuno to let them escape the crumbling tower while he remained in the building to join his wife in death.

The Final Battle
Ai and Marco appear in the third parallel world created when Yuno, Muru Muru, Yukiteru and Minene Uryu perform a time leap two years into the past. They are seen with Kamado at her Mother's Village orphanage as John Bacchus calls her regarding the future. In the anime, she is seen sleeping with Marco while she hears the commotion at Sakurami Middle School.

Two years later, Marco and Ai are seen walking together among a street of people. It is shown that Ai is clearly pregnant. In the anime, Ai chats with Marco in a cafe, telling him he must work harder in the future.

Future Diary: Paradox
In Future Diary: Paradox, Aru Akise and Muru Muru are forced to stand in for Yukiteru Amano and Yuno Gasai after Muru Muru messes up the future by killing Yuno. Akise decides to alter the game's future by saving Tsubaki Kasugano 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 she 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 Yukiteru, but Muru Muru succeeds in her task and erases Paradox's events from history.

Trivia

 * The name Ai means "love, affection" (愛) or "indigo" (藍).
 * Ai is a reference to Venus, the Roman goddess of love and beauty.
 * In Roman mythology, Mars and Venus were deeply in love with each other, which is reflected in Ai's relationship with Marco Ikusaba (who represents Mars in the Survival Game).
 * Ai's surname Mikami means "three" (三), "mindset, outlook, mentality" (見), "taste" (味), "sea" (海) or "water" (水) (mi) and "upper, above" (上), "god" (神) or "guard, protect, defend" (守) (kami).
 * It can also mean "beauty god" (美神).
 * Ai's character theme song (shared with Marco) is "7th Heaven" by Yousei Matsui and Choucho.
 * With her dark hair, combat skill, and general appearance, Ai bears some resemblance to Mukuro Ikusaba from the Danganronpa series. Coincidentally, she ends up sharing the same surname after marrying Marco (who himself bears resemblance to fellow Danganronpa character Mondo Oowada).