Akira is the roommate of Mai Tokiha's younger brother Takumi Tokiha and attends the Fuka Middle school with him. Akira's strong-willed and forceful personality contrasts with Takumi's kind and (relatively) feminine attitude and is extremely private, setting up a curtain and strict boundaries for the room. Akira is also a student of Ishigami, the art teacher.
In the 10th episode ("Cake Wars") Akira assists Takumi in baking a cake for his sister Mai and setting up a surprise party for her. When Takumi is attacked by an Orphan after sending Akira to buy icing sugar for the cake. He is then rescued by a masked ninja, who despite obviously being Akira, asks that the "Secret Ninja of the School"'s identity be kept secret by him. At the end of the episode Akira is seen disrobing to tend to a wound incurred while fighting the Orphan, revealing not only her true gender, which has been kept secret for years, but the fact that she too is a HiME. Eventually Akira's true identity is accidentally discovered by Takumi (Takumi barged in the bathroom as Akira was drying herself after a shower). Despite her orders to kill anyone who learns of her secret, she keeps Takumi alive, but makes him swear to silence. It also becomes evident that they have begun to develop deep feelings for each other, which becomes significant as the events of the HiME carnival progress. It is later shown that one of her books turns out to be her drawing book, which is filled with her drawings of Takumi. When Nao Yuuki tries to abduct Takumi as revenge against Mai, Akira intervenes with her Child and flees into the forest with Takumi. Unfortunately Mikoto Minagi is also in the forest, and influenced by the Obsidian Prince, Mikoto appears to be the one to destroy Akira's Child, Gennai, in the process taking Takumi's life, as he was Akira's most important person and had his life force connected to the Child. A distressed Akira collapses after this, and is later seen being carried off by members of her father's clan. It is later revealed, however, that Mikoto was not the one to defeat Akira and kill Takumi, but Shiho Munakata with her Child Yatagarasu in order to hurt Mai.
In the final episode she is seen under their care tied to a wooden post when Mashiro revives the fallen HiME and their most important people, including Takumi. After participating in the final battle against the Obsidian Lord, Akira travels to America with Takumi where he receives surgery for his heart condition.
Element and Child
Her Child in My-HiME, a huge frog-like creature named Gennai, is able to blind enemies with the giant spotlights on its back, allowing Akira to "pin" the enemy's shadow the ground and allow Gennai to execute its Jigoku Gama (literally "Hell Toad") attack, which involves Gennai launching a huge spiked ball out of its mouth towards the enemy. Gennai is also summoned with the long incantation "Rin, Pyou (or Byou), Tou, Sha, Kai, Jin, Retsu, Zai, Zen (Kuji-in), Gennai, Appearance!". However, since its first appearance, Gennai hasn't been summoned in this manner; indeed, since Takumi was at the scene, this could have only been an act to help disuade him from making any unwanted connections. Her Element is a double-bladed kunai that she can summon with the word "on", although she has also been seen to summon smaller shuriken to use as throwing weapons.  However, as with Gennai, this has only been the case with its initial appearance, as all others had it being summoned wordlessly.
In the manga her element is much larger, and she is never seen summoning her Child, so the identity of her Key is unknown.
In the manga Akira is blackmailed by Haruka Suzushiro into joining the Ori-HiME Team in order to keep her identity a secret. She often visits Takumi, who is much sicker in the manga, to give him notes as the class representative, though her relationship with him goes unexplored. She becomes good friends with Mikoto Minagi, who had been her enemy until they resolved their differences after Mikoto rescued her. At the end of the manga, Akira is seen wearing a girl's school uniform, Mikoto checks to see if she is wearing a bra.
Akira as she appears in My-OtomeIn My-Otome Akira is the bodyguard of Takumi, who in this universe is the son of the shogun of Zipang. She poses as Takumi when he sneaks off during a diplomatic visit to Windbloom, only revealing herself after Mashiro Blan de Windbloom and Takumi inadvertently end up spending the day together while keeping their respective identities a secret. She then fights off a SLAVE and Arika Yumemiya as Takumi begins to have an attack of an illness (presumably the same illness as he had in My-HiME). She appears to have some level of disdain for Otomes, as when she is mistaken for an Otome by Arika she says "Don't group me with those things" possibly because of the Otome Mai's unexplained disappearance, though Mai and Takumi are reunited at the end of the series and are seen together in the final scene while Akira scowls in the background.
In the manga version of My-Otome two versions of Akira exists. The first Akira is actually an Otome for Takumi, who is the king of Cardair (Zipang does not exist in the manga). She is known as the Mysterious Peridot (玄内の橄欖石 Gennai no Kanranseki) and first appears to fight the leader of the Black Valley, Midori, and then challenges Arika to a semi-formal battle. Afterwards, she is present with Takumi at Manshiro's coronation ceremony at Windbloom, and is one of the collaborated Otome under siege by Sergey's military forces. She aids the other Otome and proves to be somewhat of a match for the soldiers using only her ninja skills when the Otome's Robes are deactivated.
The HiME Akira is revived along with the other HiMEs. The two begin battling, each claiming that Takumi is "theirs". The HiME Akira eventually dies when Manshiro uses the Trinity Lover Strike to kill the HiMEs.
In every incarnation Akira is shown to be adept at ninjutsu and skilled with kunai as her main weapon. In the My-Otome manga she is also able to walk up walls and through shadows.