Hiyama is a petite young woman with large dark eyes, black hair set in a neat bob hairstyle with neatly cut bangs that fall just over her eyes, small full lips with dark lipstick applied to them and a moderately sized bosom.
Hiyama is an extremely precise woman who tracks her life to the second. However, she seems to have a crippling dislike of solitude as seen when she lost her normally calm composure after Akoya Seishu criticized her for her performance in his match. She is completely tied to Akoya Seishu, in a manner far beyond Stockholm syndrome, and views him as her saviour, despite his actions of enforcing justice going beyond reason. She has a surprising lack of modesty, like attempting to walk into a shower naked before even getting close to the shower.
Hiyama was appointed as the CEO of Wakasa Life Insurance six years ago, after the death of her father that same year. Because she lacked work experience, she received assistance from her cousin, who was the vice-president, and he soon became irreplaceable to her. However, only a year later, he attempted to murder Hiyama in an attempt to take control of the company himself. However, her cousin was killed by Akoya Seishu before he could kill her. From this point onwards, Hiyama viewed Akoya as her saviour and aided him in his single-minded pursuit of "justice".
She was first seen in her bed, with Akoya Seishu asking her how long it was till they would arrive at the island. Replying with inhuman accuracy, and adding that it was strange for Akoya to act so excited, he replied that it was because soon he would get to enact his justice.
During their first day on Ganryu Island, after spotting someone flailing in the see, Hiyama told Akoya to save them, soon finding out it was none other than Yoshitake Yoshiro.
In the first round of the Kengan Annihilation Tournament, she aided Akoya in his fight against Kono Haruo after analysing him, giving Akoya the advantage. However, after Haruo's sudden change in respiration rate, Hiyama was forced to re-analyse him, putting Akoya on the back foot. Telling Hiyama her time was up, Akoya did things his own way, brutally knocking Haruo out with a powerful kick to the face. After the fight, Akoya slapped her in the face and told her that her hesitations had impeded him and that he would be fighting alone in the next round. Pleading for Akoya not to leave her, he merely wiped the blood from her face and warned her to not let it happen again.
In the second round, Hiyama once again helped Akoya in the initial stages of his fight against Imai Cosmo, analysing him and allowing Akoya to go on the offensive. However, before she could send a signal to Akoya that would allow him to counter Cosmo's "Zone", Hiyama was intercepted by Nishihonji Akira who revealed his knowledge of their secret plan. With a hysterical Hiyama unable to lend Akoya aid, he reverted his own instincts for the rest of the fight as Hiyama explained to Nishihonji what Akoya had been doing under the radar. With Hiyama telling them there was nothing she could do as Akoya began torturing Cosmo, they all merely watched as Cosmo turned it around and attained victory. Afterwards, Hiyama was seen sitting with a visibly irked Akoya. When Nishihonji brought over a severely injured Cosmo to them and explained that the result of the fight was most important, Akoya merely left in a grump with Hiyama following beside him.
The two watched the rest of the tournament together, away from the rest of the audience.
She collected Akoya Seishu before his return fight to Kengan matches. Seeing him talking to Gaoh Ryuki before the match, she asked Akoya what he had said to Ryuki, with the Executioner replying that he would be going in for the kill in order to ascertain Ryuki's true "nature". Hiyama then watched as Akoya fought against Ryuki.
Power & Abilities
Hiyama has a perfectly precise internal clock that allows her to mentally analyse and calculate numerical problems with superhuman capabilities (with only a handful of cases globally being on her level). For example, she is able to calculate a fighter's respiratory pattern by analysing it with her internal clock.
Notes & Trivia
- Hiyama has a hobby of collecting kimonos.