Reever is a man of tall height and average build. He has messy, sandy blond hair, and is typically seen wearing a dress shirt with the sleeves rolled up, a waistcoat and tie, and casual dress pants. Over it all, he wears a lab coat, which, after the European Branch's move to the new location, gained several marks of ranking, showing his position as the head of Science Division Section One. Recently, Reever has also started wearing his hair a bit shorter, though it still stands up messily. Reever also has a slight bit of stubble on his chin, and wears two bracelets, one on each wrist.When not in uniform, Reever wears a more formal dress shirt, waistcoat and dress pants, as well as gloves. Reever has also been seen, on occasion, wearing a pair of reading glasses.
Despite becoming comically distressed when forced to deal with his superior, Komui Lee, Reever is a very focused and devoted individual. He has a very strong sense of duty to the Order and instills this duty in his team when they are fearful. Although he has no powers of his own, he is always willing to fight alongside the Exorcists, one going so far as to stand up to several Skulls when they were threatening his subordinates. Reever doesn't drink alcohol or smoke tobacco, instead preferring various soft drinks.
Previously from the Middle Eastern Branch, Reever succeeded Komui Lee as the Chief of the European Branch Science Division, though Reever tends to bend to Komui's will when the Supervisor decides to act like he is still in charge of the division.
Introduction arcEditReever is first seen when Allen Walker is attempting to enter the Order, explaining to a stunned Komui that Allen might not actually be an outsider with Lenalee Lee elaborating that Allen has General Cross Marian's golem, Timcanpy. Reever then asks Komui if he knows what's going on. Reever directs Allen to take the Gatekeeper's examination, and when Allen fails Reever is about to order Number 65 to call several Exorcists when Yu Kanda heads out. Upon Allen's insistence that Komui should have gotten a letter, Komui has his desk searched, and when the letter is found Reever demands that Komui clean his desk as Komui, ignoring him, walks away, ordering Reever to stop Kanda. When Kanda demands an explanation, Komui pulls at Reever's headset to explain the situation to Kanda, to Reever's annoyance.
Later, when Allen settles in, Reever stops Allen and Kanda from fighting in the cafeteria in order to tell them that Komui has a mission for them. They head to Komui's office to find him asleep, whereupon Reever tells Komui that Lenalee is getting married, which makes Komui wake up immediately. Reever is then present when Komui wishes Allen good luck on his first mission.
Ghost of Mater arcEdit
After Allen and Kanda have defeated the Akuma in Mater, Kanda calls the Order to report. Reever is seen briefly asking Komui to sign more paperwork, Komui then trying to drag Reever into his argument with Kanda.
The Black Order Attempted Annihilation Incident arcEdit
When Komui invents an new Komlin to try to help with the workload, Reever is first skeptical, then horrified when the robot short-circuits and announces its plans to make Lenalee muscular. Reever manages to escape the Komlin's rampage with Lenalee, meeting up with Allen when the boy returns shortly after and explaining the situation. Reever then welcomes Allen home, making Allen nostalgic before they have to resume running from the maddened robot.
Komui then sets the robot on Allen, angering Reever as the man takes to protecting Lenalee, and just when Allen is about to use his recently evolved Innocence to destroy the Komlin, Komui shoots Allen with a tranquilizer dart, to Reever's horror. Reever tries to save Allen from the Komlin when it takes him into its surgery room, but the Komlin, with Allen secure, quickly sets its sights on Lenalee.
Lenalee awakens, and Reever tells her that Allen is trapped within the Komlin, which makes Lenalee attack it. As the Komlin tries to fight back, Reever mocks it, telling it that it can't hope to keep up with Lenalee with her Dark Boots invoked, and when Lenalee cleaves the Komlin open, Reever pulls a heavily bandaged and dazed Allen out, carrying him to safety.
Rewinding Town arcEdit
Reever helps Komui explain a mission assignment to Lenalee and Allen, both of them being very vague and unsure as their information isn't solid.
The Vampire of the Old Castle arcEdit
At the same time as Allen and Lavi are fighting the, apparently vampyric, Arystar Krory III, Johnny Gill approaches Reever while revewing some old case files, asking about one that Komui never signed off on that was never filed. Reever tells him to file it, but Johnny points out that it's over eight years old, and that it has to do with a vampire legend. Just then, Komui arrives, and when Reever asks him about it, Komui says that the case had nothing to do with Innocence, but that several Finders had "fallen pray" to the vampire. Ignoring the horror of their subordinates, Komui then demands that Reever makes him coffee, and when Reever refuses, he and Komui get in an argument.
Later, when Lavi calls Headquarters to report the success of their mission, Reever is seen, again, bringing Komui more paperwork. After the phone call ends, Komui pretends to still be in the middle of a conversation, but Reever immediately sees through him.
Order in Crisis arcEdit
When the bodies of six Exorcists and one hundred and forty-two Finders are returned to the Order, Reever solemnly gives the casualty report to Komui. Several men in the observing group begin wondering how they'll survive if Exorcists couldn't make it, and Reever tells them to shut up and respect those who have returned from the battlefield. Reever then goes into further detail for Komui about a few odd deaths, explaining that a few Exorcists had a few organs removed with no external damage done to their bodies. He then reports that they haven't heard from Suman Dark.
Suman Dark's Fallen arcEdit
Upon arriving in China, Lenalee makes a call to Headquarters that is answered by Reever, who listens to her explanation of her group's plans to travel to Edo, Japan to look for Cross. Reever asks if Lenalee wants to talk to Komui, and when she says she hadn't asked because she had thought he couldn't come to the phone, Reever points out that he is asleep and wonders how she knew. Reever then tells her to be careful, making Lenalee cry when he says that he and the other members of the Science Division just want them to come home safely.
Not long after, Suman Dark returns as a Fallen One and Lenalee calls Headquarters again for council, Reever being present as Komui talks to her. When Johnny asks Reever for an explanation, Reever tells him that Suman's Innocence has taken over his body and that he will die within a twenty-four hour period, insisting when Johnny tearfully protests that Suman will die.
Edo and Asian Branch arcEdit
Noah's Ark arcEdit
When the Exorcists return from their battles in Edo and on the Ark, Reever is one of the many present to welcome them back. Later, with the Ark connecting the European Branch to Asian Branch, Reever is left babysitting Bak, who has started abusing the Ark in the name of "experimentation". When Johnny tries to point out that Bak doesn't have the authority to do what he's doing without Komui's permission, Reever silences him, but not before Sammo Han Won can start crying as he tries to get them to feel sympathy for Bak, who hasn't been allowed to see Lenalee (his not-so-secret crush).
Invasion of the Black Order arcEditOnce things have calmed down, Reever and his staff are left to study the newly obtained Akuma Egg, Reever apologizing to Lavi for not having the time to fix his Anti-Akuma Weapon. Soon after, Noah Lulu Bell invades the Science Division with an army of Level 3 Akuma, Reever getting injured and barely able to escape with his staff to attempt to construct makeshift Talismans until reinforcements arrive. When the Skulls begn killing the captured members of the Science Division, Reever is tempted to go to try to save them, only to be stopped when Bak reasons with him that Allen should have noticed something wrong. Tup Dop, though, is turned into a Skull, and Reever, unable to handle it, draws his gun and shoots the lead Skull, demanding that it take him instead of his subordinates. The Skull quickly makes to turn him into a Skull, as well, but just then Allen arrives and saves Reever.
A fight ensues, and Bookman, who has also arrived with Allen, is captured, whereupon Reever quickly blocks his attackers with a Talisman. After the Akuma have been defeated and Allen suggests that the Science Division members be evacuated so they aren't poisoned by the noxious fumes the Akuma corpses are giving off, Reever insists that his men are taken out before him, wanting to go look for some of his other men who had been taken. As he is on his way there, a Level 4 Akuma is born, and Reever is gravely injured trying to save Johnny and detain it.
The Level 4 destroys the floor and Reever is presumed to be lost in the collapse, but is later shown to be alive, having been saved by Miranda Lotto and her "Time Out". Reever calls Komui and asks for the fires in their area to be put out, and Komui hurries to find help for them. Once the Level 4 has been defeated, Reever is taken in for medical care, Komui going to his side and Bak, nearby and also injured, compliments Komui on the grit of his subordinates. Reever then asks Komui about Tup, and he, Johnny, Lenalee and Rob Neal are able to go to Tup's side just before he dies.
Reever then helps Komui give a presentation explaining Lenalee's newly evolved, crystal type Innocence, Reever explaining in detail that the Innocence, while made of Lenalee's blood, isn't in her body, and that as long as she has blood in her body it should be able to repair itself.
Destruction of the Black Order arcEdit
When the decision is made to move the European Branch to a new location, Reever is in charge of coordinating the move. Initially seen directing Noise Marie on where to put boxes, he is then exasperated when Allen falls asleep and ends up knocking a serum onto himself that makes both his and Timcanpy's hair grow, and Allen is not the first victim of similar occurrences; Bookman's hair has turned into rabbit ears, and Lavi and Kanda's bodies have shrunk down to child-like forms.
In a brief flashback, Reever is shown to have consoled Allen when questioned about the Ark, worried that Allen might think that the higher-ups who are supposed to be his friends suspect him. When Allen explains, though, that he doesn't understand how the knowledge got in his head, and that he finds the fact that he has had things implanted in his head without his knowledge disgusting, Reever looks shocked but his unable to comfort him.
After a box containing another serum is dropped on Lenalee and Bookman by Miranda and the two are stuck talking like cats, Reever is just demanding that the person who made the experiment step forward when Allen asks him if they shouldn't be worried about more troublesome things. Reever quickly assures him that the Science Division hasn't made anything "really crazy" (something Kanda immediately calls a lie), and just then the lights go out. Reever and several others from the Science Division immediately blame Komui when they hear creepy laughter, and when the Head Nurse stumbles into the room and bites Allen, Reever is one of the two to pull them apart.
Miranda is bitten shortly after, as are many others, and when they all start foaming and acting crazy, closing in on the group, Allen protects Reever and several others with his Innocence before they flee, Reever carrying Johnny. The group finds a closet to hide in, and Reever and the other "surviving" Science Division members begin plotting out possible explanations, only for Komui, in the shadows, to explain that the cause is a serum he created that causes people to turn into infectious, living "zombies". Reever orders that Komui be tied up, most in the room quickly trying to comply, but Komui uses a Komlin to tie up Reever and the others.
Reever then demands to know how Komui's virus got out, and Komui asks the question back, pointing out that the Science Division had confiscated it from him, making Reever remember that the virus is the "Komuvitan D" serum that was supposed to allow the Science Division workers to stay awake, with the unfortunate backlash of them losing their minds.
After reaching an agreement to work together, Komui unties Reever and the others and they begin to work their way through the builing, Reever asking Komui as they go how they are supposed to identify the source so they can derive a vaccine. Komui gives him a vague answer, making Reever realize that Komui has no idea how to identify the source of his own virus and making Kanda want to kill Komui; Reever initially stops Kanda, but when Komui blames the Science Division for the situation, Reever joins in on Kanda's plan to kill him. Suddenly, Generals Froi Tiedoll, Socalo and Klaud burst through the walls and attack the group, and when Komui orders his Komlin to "do something", the robot responds by launching several rockets, blowing up the hallway.
Komui regains consciousness to find Reever tying him up, Reever insisting that he has no control over his body. Komui assumes that Reever means his hatred for Komui has taken over his body and is making him tie Komui up, making Reever try to make Komui take him seriously as he insists there is something inside of him. Reever then cries out and collapses before standing, a girl sticking out of his chest and making Reever's body press a knife to Reever's neck, the girl threatening to slit Reever's throat if Komui doesn't cancel the relocation.
Komui "freezes up", unable to respond, and the girl makes Reever's body punch Komui; once he has recovered, Komui asks the girl if she is Reever's love child, which makes Reever punch Komui of his own volition. Once Komui starts to listen seriously, the girl, who reveals herself to be a ghost, asks again for Komui to cancel the move, and when Komui responds that she'll have to talk to his superiors, the girl makes Reever cut his own neck a bit.
Reever listens with exasperation as Komui goes on to explain all of the technical problems involved with trying to stop the move through him, Reever telling Komui to shut up before he cries when the girl points out that he's tying her up with red tape when she could kill Reever. The girl then makes Reever drop the knife, giving in and saying she had to at least try, and Reever listens in shock as she reveals that she had died in the building after being experimented on until her body gave out. The girl then leaves Reever's body and goes for Lenalee, calling her lucky, and before Reever can try to get the girl away from Lenalee the building shakes and they fall over.
Allen's group, being chased by the "zombies", falls into the room as the ceiling/walls are destroyed, and the ghost girl, now possessing Lenalee, has the zombie hoard untie her and tie up Reever. When the zombies lunge for them, Reever knocks Komui out of the way and saves him, blaming himself for the situation and swearing, as he is bitten, to be more strict with Komui next time, making Komui cry out that Reever only saved him so he could chastise him.
Now part of the zombie hoard, Reever ends up biting Komui, and they all remain "zombies" until Bak comes the next day to help with the move and derives a vaccine upon finding the group in their maddened condition.
Disappearance of Cross Marian arcEdit
When Komui takes Allen, Johnny and Lenalee ahead to set up Ark Gates in the new building, Reever stays behind to monitor the connection and oversee the transfer.
Almost two weeks later, Reever's title has changed from "Section Head of the Science Division" to "Section Head of Science Division Section One", the transfer to the new location having introduced two new Science Section groups with two new Science Section Heads.
Lenalee, who is back from a mission at the time, is serving Reever is coffee when Regory Peck, the Section Head of Science Division Section Two, points out that it is inappropriate for Reever to be making Lenalee serve him his coffee. When Lenalee insists that she enjoys serving coffee, Regory asks her to serve him some, as well, and when Reever notices Regory ogling Lenalee as she complies, he becomes annoyed and warns Regory that Lenalee has a brother. Reever is then approached by Mark Barrows, the Section Head of Science Division Section Three, who informs Reever that he has received complaints from his men about the fact that Reever's men, who often forget to bathe regularly, stink, demanding that they all wear deodorant. Just then, Johnny and Jiji Lujun lead in a newly transferred Cash Dop, the sister of Tup Dop, and when Reever notices the familial resemblance, he, like the others had, cries out Tup's name and embraces her, much to her annoyance.
Phantom Thief G arcEdit
When several Finders and Jiji Lujun of the Science Division are arrested for being associated with the mysterious "Phantom Thief G" and Allen, Kanda and Marie, the Exorcists assigned to the mission, are unable to negotiate their release, Reever, accompanied by the "CROW" Madarao and Tewaku, is sent to get them out of prison. There, Miss Bonnaire, a transgender male, immediately falls in love with him.
After negotiating the release of the group, including Miss Bonnaire who decides to join the Order as a Finder, Reever heads to the Hearst Orphan Asylum to help with the mission, explaining the situation to an irate and skeptical Inspector Galmar, Chief of the Parisian police, Reever welcoming the inspector to arrest the group again if he is not able to prove that Innocence is behind the Phantom Thief robberies with the stipulation that, if Reever are right, they will be able to take the Phantom Thief with them back to the Order.
The Finders locate four ladybugs on each corner of the building with odd seals on their back, Reever speculating that they are "vehicles" being used to cast the spell that is sealing the orphanage from the outside world, and after one of the ladybugs is removed, disrupting the spell rather violently, Reever is electrocuted by the shock. Jiji then points out to Reever that his CROW guards aren't who they appear to be, Madarao having been able to enter the building earlier unassisted.
Reever and the Finders head inside to check on things, and when they find the children of the orphanage running high fevers, Reever concludes that they've been poisoned by Dark Matter and sends in a request for an Ark Gate so the children can go to Headquarters for treatment.
Third Exorcists arcEdit
At the North American Branch, Reever watches over Johnny as he is violently sick in the bathroom, getting annoyed when he notices that Regory and his assistant are also present. When Regory then gets mad at Johnny for making a scene during whatever they had been witnessing, blaming Johnny for him not being able to see "Alma Karma", Reever forcibly removes Regory from the bathroom, apologizing to him with lacking sincerity before he turns his attention back to Johnny, apologizing for making him see what he had.
Just as Johnny asks Reever why he had brought him to the meeting, an invasion warning sounds over the loudspeakers of the building, shocking Reever.
Mystery of Kanda arcEdit
Thirty minutes before the invasion, Reever, in an underground chamber bearing magic seals and surrounded by his Science Division colleagues, calls Johnny forward to observe the unconscious body of Alma Karma. He observes Johnny's shocked expressing when the younger man realizes that Alma is just a child, and when Johnny throws up on Regory upon learning of Alma's dark past with Kanda, Reever turns his concerned attention to Johnny, only to have to cover his ears when Regory screams indignantly.
Reever then escorts Johnny to the bathroom, where the story catches up to the present with the invasion. After helping Johnny to his feet after he falls, Reever joins Regory and his assistant in running to an underground shelter, only for the Noah Sheril Kamelot to seize control of their bodies along the way. As they are forced to walk back to Alma's chamber, Reever realizes that they are being controlled somehow, and that the level of silence in the building indicates that the entire building has been taken over.
They arrive in Alma's chamber to find that the Earl of Millennium, as well as Sheril, Wisely, and Road Kamelot, accompanied by several Level 4 Akuma, have taken control of the other scientists, as well. Johnny alerts Reever to an unconscious and injured Kanda's presence, and when Allen arrives, along with Tyki Mikk, Reever apologizes to Allen sheepishly, along with Johnny. Reever is then mortified alongside Johnny and Regory when Sheril warns Allen that, if he doesn't comply with the events that are to unfold, he'll "bend [Reever and the others] into horrible shapes".
The Earl then taunts the Fourteenth into showing himself, making the Fourteenth reveal his plans of taking over as the next Earl, and Kanda regains consciousness and runs out of the way with Allen and Tokusa as the Noah pull Alma out of his tank. When presented with Alma, Kanda claims not to know him, much to the shock of Reever and the others. Wisely then submerges Kanda, Allen, Road and Alma into Kanda's memories, leaving Reever and the others to observe from the outside.
Allen regains enough control of his body to break Wisely's control, and once he does the pipes in the room start rearranging, wrapping up Reever and the other scientists in a painfully tight hold. Alma Karma starts to awaken, turning into an Akuma and emitting a powerful blast of Dark Matter that simulates a wave of the Akuma Virus, which seemingly kills Reever and the others. Tokusa, though, manages to save them, only to turn into an Akuma-like creature, himself, when the Alma cells within him go berserk as the now conscious Alma starts to fight Kanda.
The Earl offers to remove the Dark Matter from Alma's body if Allen agrees to join him, much to Reever's shock. Alma and Kanda, though, continue fighting, and Tokusa, his Alma cells mistaking Bak for his father, Edgar Chang Martin, attacks Bak with a lightning-like attack, which spreads and hurts Reever, as well. Bak then uses the "Spirit Stone" on his hat to use a magic to slow Tokusa down, urging Allen to not worry about them and to go and stop Alma, Reever and Johnny urging Allen to do the same.
Allen attempts to calm a maddened Kanda and protect Alma, but Kanda cuts Allen with his sword, as well, to Reever's shock. Bak's spirit stone then begins cracking, making the energy attack Tokusa is still releasing on Reever and the others increase in power enough to hurt them again, though Reever remains more concerned with Kanda and Allen as the two begin earnestly fighting each other. When Kanda stabs Allen, to Reever's horror, Kanda is shocked by his own actions, giving Alma the opportunity to attack Kanda again and making Johnny call out for both of them to stop.
Before Alma's attack can be fired, Allen's body releases a powerful pulse and floats, and when the Earl thanks Kanda for stabbing Allen and awakening the Fourteenth, Reever realizes that the Earl had planned for Kanda and Alma to fight for this very reason from the very beginning. Allen, though, awakens from the Fourteenth's control and sees Alma for who he really is (his soul being that of a woman Kanda's previous life had loved), and when this pushes Alma to self-destruct, Reever calls out for him, yet again, to stop.
Kanda and Alma both survive the blast and reconcile, and Allen gives them the chance to run away together, promising to stand between them and the Order as he sends them away through an Ark Gate. Tokusa, though, stays in his maddened state, and Allen turns his attention to trying to awaken him, ignoring Malcolm C. Lvellie's orders to go after and kill Alma. Howard Link, though, arrives and binds Allen before he can save Tokusa.
Seed of Destruction arcEdit
When Tewaku, believing that Allen killed her brother, Madarao, tries to attack Allen, an enlarged Timcanpy arrives and knocks both her and Allen aside, stunning Reever and the others with his new size. The Earl then kidnaps Tokusa and Tewaku before retreating.
Upon returning to the Order and having his injuries tended to, Reever eats ravenously with the others in the cafeteria, encouraging Lenalee to do the same so they can build up their strength in order to help Allen. An anonymous bystander throws eggs at them, proclaiming that Allen should be executed and accidentally hitting a nearby, unnamed Cardinal. Reever apologizes to him and invites him to sit at their table, but the Cardinal politely turns him down before assuring him and the others that Allen will not be executed.
Later that evening, there is an explosion in the building and Allen is seen by Jiji retreating with several Noah. Jiji reports this to Reever, who is stunned and unsure what to think.
Searching for A.W. arcEdit
Three months later, Jiji notices Johnny acting oddly and makes Reever and Cash observe Johnny's new behavior with him. When Johnny goes into the archives and pulls out Allen's files, which have been sealed and labeled classified, Reever approaches him and reminds him of this, ordering him to put it back. Johnny then turns to Reever and expresses his desire to resign from the Order, much to Reever's shock. When Reever asks if Johnny plans on going to Allen, Johnny just bows and thanks him for their time together.
Reever refuses to give his consent to Johnny's wishes to resign, which keeps Johnny from being able to, so Johnny continues trying, even begging him when Reever receives a phone call informing him of Zu Mei Chang's death. Reever refuses to believe Johnny's excuse (which involves going to his bedridden, sick grandmother's side to take over the family tailoring business), insisting that he knows that he's going to try to find Allen and telling Johnny that it is too dangerous. Johnny reminds him that the Science Division exists to support the Exorcists, and surmises that leaving Allen alone is just giving into what the Fourteenth wants, and Reever, convinced and comparing Johnny's resolve to the resolves of himself and Komui, tearfully gives his consent.
Before Johnny leaves, Reever gives him the tie that he, himself, had been wearing when he entered the Order, which has a medal depicting St. Christopher, who watches over travelers, sewn into it. Reever then reminds Johnny that, once he leaves the Order, they can't help him anymore, and after Jiji and Cash wish him luck, Johnny leaves.
Abilities and SkillsEdit
Vast Scientific Knowledge: As the Chief of the European Branch Science Division Section One, Reever is a very knowledgeable scientist, the Science Division of the European Branch, itself, being a very difficult area to transfer into, thus inferring that the Science Division Chief would be part of the elite. Reever, himself, specializes in Chemistry, Mathematics and Linguistics.
Marksmanship: Reever is noted to be a skilled marksman, the practice of precision shooting being a hobby of his. He also seems to carry a gun on his person, presumably at most times, and is seen using it against a Skull, where he shot it cleanly through the temple from several yards away.
Good brain: Reever was stated to have a "good brain" and thus to be able to become a skull.
Komui Lee: Reever is the chief of Science Section, making him a subordinate of Komui. Komui seems to be closer to him than to other section chiefs and they seem to be together for a good amount of time. Reever appears more competent with paperwork and he has done a lot of it instead of Komui. Yet Komui formerly hold Reever's position and because of that he often resume his old job instead of its current one. This often leads to catastrophes because of his weird inventions. Reever seems particularly fearful of these and he doesn't hesitate to stop his chief forcefully. It can look like Reever hates him but he actually respects him a lot. Komui on his side takes care of Reever like he does with all his subordinate.
Johnny Gill: Johnny is a close subordinate of Reever. He heavily trusts him and even made him his personal assistant. He allowed him to go with him at the Alma Karma meeting and seems to hold high hopes for Johnny. He reveals that the took him because he always had esteem for him, not only for his scientific skills but for his ability to understand exorcists and wanting to protect them. To some extent Johnny reminds him of himself. More precisely his relation with Johnny reminds him of his own relation with Komui.  In return, Johnny highly respects his superior. Reever is a rather cool superior even if he can be firm sometimes. During the Searching for A.W. arc, after refusing a thousand times Reever understood Johnny feeling and finally let him go. Johnny was very touched.
- Reever enjoys marksmanship, doing cross puzzles and running marathons. He likes maths, linguistics, Lenalee's lemon tea and sodas and he dislikes alcoholic drinks, the Komlin series and superiors who don't work. 
- Reever was included in the game Jump Superstars.
- It is mentioned that Reever drinks lemon flavored soda. This is because Komui kept mistaking Reever's cola for coffee.