Aki Hayakawa

Aki Hayakawa (アキ) was a Public Safety Devil Hunter, working under Makima's special squad. He had contracts with the Curse Devil and Future Devil, and a former contract with the Fox Devil. He was killed and possessed by the Gun Devil, thus becoming a Gun Fiend (銃の魔人, Jū no majin).

Appearance
Aki Hayakawa is a handsome young man with medium-length black hair and green eyes. He usually wears his hair in a topknot style. He often wears a suit and tie. He also wears earrings and usually carries his sword on his back.

Personality
Aki generally appears to be a very stoic person. He acts mature and dependable when he's with his fellow Devil hunters, but is actually very soft when he is alone. He has a tendency to get attached to others easily, and hates to see people get hurt, especially his close friends. Unlike many of his associates, he is described by Himeno as being a "normal person", in the sense that he still grieves for those lost and has not become jaded enough to close his feelings off. Despite this, he is very determined and his primary motivation for killing the Gun Devil is revenge for his family. He is, however, entirely willing to put his own life on the line to save other people despite his own fear of death and even at risk to his ultimate goal.

His air of cold detachment is actually a facade, and he has been seen to cry over the deaths of his comrades such as Himeno, and he grew to care for Denji and Power enough to try and forfeit his revenge goal in order to keep them safe.

Denji
Aki and Denji initially hate one another, with their first mission ending up in a physical and verbal altercation, wherein Aki insults and punches Denji, only for Denji to knee him in the crotch and kick him while he's down. He thinks Denji is a simpleton, a brute, vulgar, and too unthinking to continue in a dangerous line of work. Despite the fight, they continue to work together due to Makima's request. Also at Makima's request, Aki allows Denji to move in to his home and takes care of him. After fighting alongside each other and living in the same household, Aki begins to consider Denji as a close friend, although he still finds him obnoxious at times. He even goes so far as to request the Fourth Division be exempt from fighting the Gun Devil in an attempt to keep Denji and Power safe.

Power
Aki and Power also have a less than positive relationship at the beginning, although perhaps not so much as with Denji. Aki dislikes Power's vulgar and ungrateful attitude, and finds her extremely obnoxious. He also takes in Power when Makima requests it, and gradually the two warm up to each other. While he seems embarrassed and annoyed by Power's constant escapades, he considers her a friend as well. Protecting Power is another reason why he wanted the Fourth Division to withdraw from fighting the Gun Devil.

Himeno
Aki has known Himeno since joining Public Safety, and she was his first work partner. She was the one responsible for getting him into smoking, and she also attempted to get him to quit his job in order to ensure his safety. She had a crush on him, although it seems that Aki did not return her feelings. He did consider her a dear friend, and he cries in the wake of her death.

Makima
Aki has a crush on Makima and seems to trust her deeply, although he could never recall why. Makima has an utter disregard for Aki's feelings, and was not interested in him beyond his use as a tool.

Intro arc
When Hayakawa is first introduced, Makima orders Denji to work with him. While they are patrolling the city Hayakawa becomes annoyed with Denji asking whether Makima has a boyfriend and pulls him into an alley to beat him up, as a warning that if he doesn't take Devil Hunting seriously he could end up dead. Denji then fights back, kicking him in the groin multiple times and stating that he would risk his life to continue living the way Makima has shown him. Once they get back to the Devil Hunters Headquarters, Makima assigns Denji to Hayakawa's squad.

Bat Devil arc
Aki drives Makima from her meeting with her superiors. In the car, Makima explains to Aki that she is interested in Denji because of his ability to transform into the Chainsaw Devil.

As Denji is impaled by the Leech Devil's tongue, Aki arrives at the battle. He summons the Fox Devil to devour the Leech Devil and save Denji. After taking Denji to the hospital, Aki explains that he was able to summon the Fox Devil as he made a contract with it. In exchange for the summoning, he must allow the Fox Devil to eat a part of him. Aki expresses his disdain for devils to Denji, claiming that they cannot be trusted. Aki informs Denji that he knows that Power tried to kill him, which Denji denies. Aki then threatens to report Power, along with Denji for covering for her, and have them executed if they do not obey his orders as their superior.

Makima informs Aki that Power is going to be moving into Aki's apartment, to his dismay. Both Aki and Denji yell at Power for never bathing or flushing the toilet.

Gun Devil arc
Aki is killed by the Gun Devil as it advances towards Makima. The Gun Devil then possesses his corpse and they become a Gun Fiend. Within this new form, he returns to his residence in order to ambush Denji. Within his mind, Aki hallucinates the experience as if he is having a snowball fight with Denji. Using his left arm, which became a gun, he fires at Denji, destroying his apartment and tearing Denji in half. He and Denji then engage in combat, which causes many building to be destroyed due to his attacks. Denji eventually succeeds in defeating Aki, killing him.

It's later revealed that in his will he left half of his money with Denji and the other half with Himeno's family.

Antemortem Abilities
Swordsmanship: Aki is a proficient swordsman, wielding a sword as his primary weapons when fighting devils.

Curse Devil Contract: Aki has a contract with the Curse Devil which grants him a nail-like sword. In order to use it, Aki's life would be significantly shortened.
 * Stab: Aki points the nail anywhere on his targets body, he then says the word "fire" the curse devil's hand appears and flicks the back end of the nail to inflict damage.
 * Curse: By stabbing his enemy three times with the nail, Aki can summon the Curse Devil to seize the enemy and inflict a curse upon them to kill them.

Future Devil Contract: After losing favor with the Fox Devil, Aki was taken to the Future Devil which is held prisoner by Public Safety, and he managed to gain a contract to use its abilities in exchange for letting the Future Devil live inside his right eye.
 * Precognition: Aki has the ability to see a few seconds into the future. He uses this to predict his opponent's oncoming attacks and plan accordingly.

Fox Devil Contract: Aki Hayakawa had a contract with the Fox Devil. In exchange for feeding him a part of his body Aki could enlist his power in combat. Aki lost the ability to summon him after he used the Fox Devil recklessly against the Katana Man.
 * Summoning: Aki could hold up his hand and say the word "Kon", causing the Fox Devil's head to appear over his target's body, swallowing them whole or cutting them to pieces where they would intersect with the Fox Devil's bite.

Postmortem Abilities
Bullet Firing: As a Gun Fiend, he is able to fire bullets from the gun in his left arm with great precision and speed. He is able to break the walls and Denji apart with ease.

Blood Consumption: As a Gun Fiend, Aki Hayakawa's corpse is able to restore his health by consuming blood.

Trivia

 * Aki Hayakawa's ranking in the Popularity Polls are as follows;
 * Aki ranked 3rd in the First Popularity Poll, with 25,704 votes.