Hiro Nimura

This page contains major spoilers for the Oneirosea series.

Hiro Nimura
Profile
Species:	Lucid Changeling
Age:	18
Pronouns:	he/him (formerly) he/she
Height:	169cm
Birthday:	March 9th
Professional Status
Affiliation:	Alcyon Corporation
Type:	Diver (Artificial)
Division:	Offense
Rank:	Sunlight

Hiroyuki Nimura (二村 洋之, Nimura Hiroyuki), more commonly known as Hiro (ヒロ), is the main protagonist of the Oneirosea series. He is an idealistic young diver who joined Alcyon Corporation in order to follow in the footsteps of a mysterious agent who saved his life eleven years prior. He currently works in the Offense Division, as part of a team with Ichika Sasaki and Clover.

Appearance

Hiro is a young person, slightly on the short side for a boy of his age. He has ear-length blue hair in a spiky style, with two strands of hair sticking up out of the top of his head. His right eye is dark brown, while his left eye is an orange prosthetic eye with a concentric circle pattern inscribed in the iris.

His usual outfit is a modified version of the Alcyon Corporation uniform (white dress shirt, black tie, black slacks, and orange armband with the sunlight rank badge on the left arm). His shirt is short-sleeved, and his pants are rolled up to his mid-calves. His shoes are white and orange sneakers instead of the standard loafers. He also wears a blue jacket with the number "16" printed on the back, usually tied around his waist.

11 years ago, both his eyes were dark brown. He had black hair, slightly shorter but in a similar style.

Demon Form

Hiro's demon form resembles a long, sinuous dragon. Her ribbonfish-like body is covered in small soft scales, which are pale blue on the back and white on the belly. She has two large wings which resemble hands or lobed flippers, and no other limbs. A single backward-curving horn with a red tip protrudes from her forehead, followed by a ridge of red fur that runs down the spine and wraps around the base of the neck to form a collar mane. She appears to have six eyes, but when her mouth opens it is revealed that this is an illusion created by three double-pupiled eyeballs floating in the center of the mouth, each of which is visible through a pair of "sockets" on either side of the head.

Personality

Hiro is an energetic and impulsive person who is perhaps most defined by his optimism. In his own words, his near-death experience has taught him to be thankful for everything. He loves to try new things, especially desserts and drinks, and is easily suckered into buying things branded as "new" or "limited time". He habitually assumes the best of everyone, brushing off any insults or rudeness without taking offense, and is eager to help with whatever problems they may have. As such, he gets along with most people he meets. On the other hand, this unfailing optimism can come off as excessive or even disturbing at times. Most notably, he speaks very casually about the tragic events in his past, giving some the impression that he's callous or uncaring. He has very few close friends, in part due to this.

His past experience with possession has left him with a memory disorder. He only remembers bits and pieces of his life before the incident. His short-term memory is also unreliable: he struggles to remember certain people's names and/or faces, and sometimes forgets parts of his everyday routine (eating, getting to work on time, etc.). Occasionally, he remembers completely fabricated events and becomes very confused if the contradiction is brought up. Although he has come up with many strategies to cope with this and is functional in everyday life, he still assumes that everyone else knows better than himself because of his unreliable memory. He is very trusting of people who present themselves as authority figures, and generally defers to others' opinions without thinking about the issue for himself, a trait that infuriates Ichika.

Overall, he gives the impression of being somewhat scatterbrained, but he's more clever than he seems. This is evident in the way he notices small details others don't, and comes up with ingenious combat tactics on the spot. His cluelessness is partly an act, put on to avoid uncomfortable questions about his identity or worldview. He is especially distressed by evidence of Alcyon Corporation's wrongdoings, since he idolizes them heavily for having saved his life, and doesn't want to acknowledge that they aren't perfectly benevolent. However, it seems that he is trying to change this way of thinking after the Goodwill Festival Arc.

Although he is very outgoing and talkative as a teenager, Nanami Murakami claims that he was very different as a child. She describes six-year-old Hiro as a quiet and sensitive boy who felt awkward approaching new people, and she was shocked to see him act so friendly upon reuniting with him in the present. It is implied that these changes came about partly due to influence from the demon's soul, since she was depicted as more cheerful and outgoing with a great passion for the human world.

History

Hiro was born in Semikawa and had no siblings. Until eleven years prior to the beginning of the story, he lived in an apartment building in Semikawa with his parents. Nanami Murakami lived on the same floor of the same building and was very similar in age to him, so their parents often set up playdates and he managed to make friends with her. Aside from this, he was a shy and awkward kid who struggled to get along with his peers, so he never made any friends.

One day when Hiro was seven, his parents left to take care of urgent work matters and left him in the apartment alone. He had intended to stay up and wait for their return, but fell asleep in front of the TV. While he was asleep, a mass changeling invasion hit the city, and he was one of the people possessed. He does not remember much about being possessed, but it is known that he lost his left eye during the experience.

Demon Side

The demon that possessed Hiro lived in the midnight zone of oneirosea. She was friends with Laplace, though both were nameless at the time and only recognized each other through appearances and auras. Eleven years ago, Laplace asked her to join the changeling invasion faction with them, reasoning that if they stayed in oneirosea they would eventually drift apart, but they could build permanent identities and remain friends in reality. She was reluctant, but ultimately accepted.

On the day of the invasion, she bid farewell to Laplace and went to choose a sleeping human as planned. She chose Hiro, rationalizing that possessing a younger human would mean killing fewer years' worth of experiences than an adult. However, once she gained possession of the body, she was shocked by its fragility. She was afraid she would break it if she caused chaos in reality like planned, and spent most of the time until she was exorcised fleeing from Alcyon Corporation's agents and other changelings instead.

Since Hiro was incompletely exorcised at the last second, he became a lucid changeling. Present-day "Hiro" is essentially a new being, containing most of the souls of the original Hiro and the demon. However, since he wasn't aware of this at the time, he took on the identity and name of Hiro and continued living as him.

After the Invasion

When he regained consciousness, he was in an unfamiliar place, and a mysterious woman wearing the Alcyon Corporation uniform was standing over him. After making sure he was fully awake and able to walk, she quickly explained what was happening, and pointed him toward a nearby shelter. Hiro attempted to ask for her name, but she disappeared without giving an answer.

He made his way to the shelter, where he was treated by Alcyon Corporation's medical division. Since he had lost his memories and did not carry any form of identification on him, it took several days for his identity to be confirmed, during which he lived in the shelter. Finally, it was confirmed that his parents had died during the invasion, and he was sent to live with an aunt in another district of Semikawa. He lost contact with Nanami and never contacted her, as he did not remember her name.

At first, Hiro found it difficult to live with his aunt; since he had no memory of her, he was often frightened or confused when she acted overly familiar with him, or assumed that he must be traumatized from an event he did not remember. These feelings were amplified during holidays and festivals, when they would meet up with other relatives who treated him the same way. As he grew up, he learned to understand and cope with these situations; however, he remained uncomfortable and awkward in her presence, leading him to spend much of his free time shut up in his room or exploring the city in various attempts to avoid her.

For the first few years after the incident, Hiro was mostly focused on managing his memory loss and catching up on schoolwork. Once he got a handle on his condition, he struggled to decide what to do with his free time, since he had no hobbies or close friends. With no other important memories to cling to, he fixated on the mysterious woman and grew to greatly admire her as the hero who saved his life. It became his goal to join Alcyon Corporation and follow in her footsteps. To this end, he spent many hours at a time studying and researching the company, sometimes to the detriment of his grades at school.

When he was 16, he landed a part-time internship position at Alcyon Corporation and used this as an excuse to move out (though his aunt continues to support him monetarily). His position was mostly clerical, managing records and general office tasks, and he did not have much contact with the company's demon-slaying or research endeavors. He used his first paycheck to buy the blue jacket he now wears over his uniform: since 16 was his age and can be pronounced as "Hiro", it immediately caught his eye, and he sees it as an important symbol of his hard work to this day.

Shortly before the start of the story, he was accepted into the Offense Division and took a demon cell in order to gain a mare.

Powers & Abilities

Immense Mist Capacity: Hiro's natural supply of mist is enormous, allowing him to fight continuously for much longer than his peers. His mist signature has been mistaken for a hadal ranked diver's on multiple occasions. Irie Miwa has noted that he has more than enough potential to manifest a natural mare, and the fact that he didn't was down to simple luck. His mist aura is white, occasionally with blue or orange edges.

Novice Mist Control: Due to the sheer amount of mist at his disposal, Hiro struggles to contain and control all of it. His aura is constantly active, making it impossible to hide from anyone with decent mist-sense. Through training, he has grasped a few basic boosting and spell techniques, but still has little control over the strength of the techniques.

Vent: Since Hiro has a human body, she does not have built-in vent slots, and is limited to projecting parts of her demon form through fresh wounds. This usually takes the form of small patches of scales, but horns and wings can also be vented from sufficiently large injuries. She can also vent a demon eye through her left eye socket, temporarily replacing the artificial eye.

Mare

Maxwell's Demon is a weapon-type mare that takes the form of a longsword with a black handle and silver pommel. The sword's blade has two symmetrical edges: the dream edge is bright orange while the waking edge is cyan. Hiro can summon and dispel this sword at will.

• Dream Edge: If Maxwell's Demon is swung in such a way that the dream edge makes contact with the target first, then it will phase through any physical object in its way and "cut" the target's mist instead. If used to cut a demon or human enemy in this way, it siphons away an amount of their energy proportional to the part of the blade that makes contact and the amount of time that contact is sustained. By making enough cuts, Hiro can deplete an enemy's mist supply and put them out of commission - humans depleted in this way temporarily lose their ability to use mist-based abilities, while demons dissolve and die, freeing any bodies they were possessing. However, the dream edge cannot do any damage aside from this, nor can it be used to defend or block attacks.
• Waking Edge: If the waking edge makes contact first, Maxwell's Demon behaves like a regular sword (i.e. can be used to cut an opponent or block/parry attacks).
• Energy Slash: By swinging the waking edge, Hiro can release the mist absorbed by the dream edge in a crescent-shaped energy wave.
• Dual Wielding: Hiro can split Maxwell's Demon into two cutlasses and wield one in either hand. Each sword maintains the properties it had as the corresponding edge of the broadsword.

Mantle

Twilit Demon is a shift-type mantle. To activate it, Hiro stabs the broadsword form of Maxwell's Demon into the ground, causing a ring of energy to burst from the ground and engulf him. Orange-red plate armor resembling Dragonscale manifests over the left side of his body: half a knight helmet visor with a horn that resembles his demon form over his forehead, a pauldron, a gorget, a clawed gauntlet, and a set of tassets over the upper thigh. The bangs framing his face grow to about chest length. Both edges of the sword become cyan.

Twilit Demon burns large amounts of mist to stay activated. In order to use it for more than one minute without running out of energy, Hiro must continually absorb mist from opponents or their attacks using dream guard, then channel it into maintaining his mantle. As such, it is best used against large crowds of demons, or a single enemy with high mist capacity that he can reliably make contact with.

• Enhanced Mist Control: Twilit Demon grants Hiro finer control over his own mist and aura. This drastically increases the effectiveness of his mist-boosting, granting enhanced strength and speed.
• Enhanced Vent: The enhanced mist control also allows Hiro to vent without having to rely on physical slots.
• Flight: By venting both wings of her demon form, Hiro can fly at extraordinary speeds. While not inherently a mantle power, this is not possible outside of Twilit Demon, as a pair of wounds deep enough to vent two large wings through would likely kill her.
• Waking Blade: While Twilit Demon is active, both sides of the broadsword behave as waking edges. Hiro can summon and dispel multiple copies of the broadsword at will, and remotely launch them in any direction. This allows him to use them like projectiles to engage opponents from a distance.
• Dream Guard: The properties of the normal mare's dream edge are granted to the armor that is manifested when Twilit Demon activates, as well as any additional armor manifested through Dragonscale. This allows Hiro to parry and absorb most incoming mist-based attacks, using the gauntlet or Dragonscale-armored wings. Additionally, mist absorbed in this way is converted and added to his aura, allowing him to repurpose it and use it for basic mist-manipulation abilities or maintaining his mantle.

Wake

Dragonscale is an unclassified wake. At will, Hiro can grow jagged, dark red scales from vented demon form parts, which serve as armor. He can also launch the scales as projectiles, which ignite and explode if they successfully embed themselves into a target.

While the scales are strong enough to deflect bullets, their use is limited in practice, as Hiro can only summon them from areas where he has already been injured unless Twilit Demon is active.

Relationships

Ichika Sasaki

Ichika is Hiro's senior in the offense division and the leader of his team. Although Hiro tries to follow her orders and be respectful, he often unintentionally angers her: he struggles to grasp what Ichika considers to be simple concepts, and can never remember her surname despite his best efforts. In turn, Ichika often snaps at him or criticizes him. Despite this, he quickly grows fond of Ichika, and considers her a friend not long after meeting her. His optimistic nature means he's unbothered by her insults, so he isn't fooled by her cold exterior and sees her as an observant leader who cares about her subordinates.

Over time, the two become close friends who keep each other grounded, despite Ichika's claims to the contrary. Outside of work, Hiro often invites Ichika to hang out with him, helping her enjoy the present and focus less on her ideal future. In turn, when Hiro tries to ignore uncomfortable truths, Ichika forcibly drags him back to reality.

Clover

Clover is Hiro's teammate, and later, roommate. Since they're both outgoing, high-energy people, they clicked immediately upon meeting each other and became best friends. Additionally, Clover knows about the mysterious woman that Hiro is searching for, so Hiro has stuck to them in an attempt to find out more.

Being friendly and helpful, Hiro is happy to assist in Clover's various "experiments", even if it means doing inadvisable things or getting injured. He often teaches them about human society and interesting places to visit as well. However, he worries about Clover's recklessness, often fretting that they'll get themselves killed or decommissioned, and pays extra attention to their actions during missions.

Nanami Murakami

Hiro and Nanami were childhood friends with a close relationship. When he was young, Hiro was sensitive and shy; Nanami often protected him from bullies, or got into arguments with other kids on his behalf.

When they coincidentally run into each other again in the present, Hiro is excited to rekindle the acquaintance and get to know her again. They share some common interests and find it easy to talk to each other. However, her presence makes him somewhat uncomfortable, as her anecdotes and reactions remind him of the incident in his childhood and how much things have changed since then. He sometimes plays dumb in order to avoid talking to her, especially when she expresses romantic interest in him.

Gallery

Trivia

• Nimura means "two villages", possibly referencing the dual nature of Hiro's soul. His first name is written with the characters 洋 (sea, foreign) and 之 (of, what). His name may also be a pun on the English word "hero".
• Hiro's employee ID is 145 674 808, which is a Happy number.
• Maxwell's Demon is likely a reference to the thought experiment of the same name, about a hypothetical being that can decrease entropy by separating high-energy and low-energy molecules.
• His cybernetic eye doubles as a smartphone, and has many of the same functionalities - apps, games, alarms, a flashlight, etc. This is considered unusual in-universe, but he finds it more convenient than a traditional phone because it is harder for him to misplace.

• Hiro is the best cook in his team. He specialty is stir fries and stews.
• After his possession, Hiro modded his hair into the same shade of blue as his mysterious savior in order to imitate her. He also attempted to grow his hair out for the same reason, but gave up due to it being too much trouble to maintain.