What kind of city are we running when we depend on the support of a potential madman!
~ Reeves condemning Batman in his campaign speech
Arthur Reeves is a major antagonist in Batman: Mask of the Phantasm. He was a corrupt Gotham City councilman who was secretly involved with Salvatore Valestra's gang, making him responsible for the events of the movie where Andrea Beaumont became the Phantasm.
Reeves was initially a lawyer of Carl Beaumont, a financial planner who was affiliated with the mob. Beaumont would refer to Reeves as "hotshot". Reeves also became good friends with Beaumont's daughter, Andrea and met her ex-fiance Bruce Wayne at some point. When Beaumont had to flee Gotham with his daughter to escape Salvatore Valestra, he turned to Reeves for help. Afterwards, Beaumont kept in touch with Reeves while he and Andrea lived hidden in Europe.
Years later, Reeves started campaigning for an alderman position in the Gotham City Council. Reeves lost funds for his first campaign. Reasoning that he was going to loose unless he amassed more capital, Reeves contacted Beaumont for help. Unfortunately for Reeves, Beaumont was unable to help since his own money problems did not grant him a surplus disposable income to be expended on electioneering and also because Beaumont didn't want to risk that the mob would discover his assistance of Reeves' campaign and trace the financial transactions back to his and Andrea's location. Now letting his ambitions cloud his morality, Reeves went to Salvatore Valestra and promised to prove information on Beaumont's whereabouts. After accepting the information from Reeves, Valestra agreed to finance Reeves' campaign and gave the candidate inside information of the Gotham leadership, which would serve both men as Valestra now had a friend in high places and Reeves had some control over the Gotham political machine early in his career. Reeves did not seem to be haunted by betraying his former mentor, and rationalized that since Beaumont owed money to Valestra, the time had come for him to pay up; Reeves was either aware or unware of this as Beaumont had already repaid the Valestra syndicate what he had owned them, but by that point, they had wanted Beaumont to repay them in blood, not cash (for failing to meet the original payment deadline, and for skipping town on them), sending Valestra's accomplished hitman and chauffeur Jack Napier to assassinate Beaumont. Years later, a vigilante known as the Phantasm started killing associates of Valestra, causing Reeves to have the police hunt Batman, thinking he was committing the murders. Although appearing as if he wanted Batman to be brought to justice for his supposed crimes, Reeves was actually worried that Batman would go after him due to his mob ties and that he would lose money if that happened as well as the end of his career.
Despite their efforts, Batman succeed in evading the police, enraging Reeves. Joker eventually tracks Reeves down to his office, informing him Batman wasn't the one who assasinated Sol, Bronski, and Valestra, but someone else (while Joker killed Valestra himself to bait his would-be killer). Joker also believes Reeves to be the Phantasm (or hired him), as he knew about the mob and sold Carl out to them. Realized what Joker was implying, Reeves denies any involvement in their murders. Andrea then contacted Reeves and Joker realized that she was actually the Phantasm, and poisons Reeves with with Joker venom, no longer having a use for him.
Reeves later appears in the Gotham City Hospital, having been driven insane by the Joker's chemicals. Batman confronts Arthur and demands to know why Joker visited him. Reeves then tells Batman of his connections to the mob, although does not give him any information regarding the Phantasm, as he didn't know her identity. Batman leaves Reeves, denying him curing as punishment and leading the doctors to come to the room to sedate Reeves once more. It's completely unknown what happened to Reeves afterwards, but as it's implied that only Batman knew the cure for his condition, it may be possible that Reeves' condition worsened until he eventually died or that he spend the rest of his days in complete madness unless anyone was able to find an alternative cure for him. However, it's likely that in any case, Reeves' political career was ruined for his condition if not for his corruption.
The New Batman Adventures
Though Arthur Reeves doesn't make any appearance in the Batman: The Animated Series follow-up show The New Batman Adventures, he makes a non-physical cameo in the episode "Beware the Creeper". In the episode, to celebrate the Joker's seventh anniversary after his fall into the chemicals that changed his life, Jack Ryder narrates a documentary about the Clown Prince of Crime's life, including facts about his early days as a hitman for the Valestra family, even showing one photograph in which Reeves appeared along the Joker, Chuckie Sol and Carl Beaumont. So, whatever Reeves' fate was, it's highly assumed that, even if he was still alive or not, Reeves' reputation as an honest politician was utterly destroyed either unknowingly or posthumously.
Arthur Reeves returns as main antagonist in the seemingly canonical Batman Adventures issue "Batman & Robin Adventures Annual #1". However, given that the comic book series contradicts several pieces of the established DCAU canon, it may or may not be non-canonical.
After Andrea's assumed death, Arthur was cured of his condition and Bruce sought to get information regarding her from him, however, he was of no help. To make matters worse, Arthur later suffered from an allergic reaction to the toxins Joker used on him, which forced him to smile at all times, driving him insane. Blaming Phantasm for what had happened to him, Arthur spent his resources seeking to discover the assassin's identity, eventually discovering that he was Andrea all along.
Seeking to get revenge, Reeves ordered the assassination of Bruce Wayne, knowing that Andrea would be drawn back out to defend her former lover. The attack succeeds in drawing Andrea out, as well as another by his henchman Kitsune, and Reeves has Andrea kidnapped while she is with Wayne at his mansion. After inspecting the Phantasm gear, Reeves reveals himself to Andrea as the mastermind behind her kidnapping and explains his motivation for wanting to have her killed. Before Reeves can have Kitsune slit Andrea's throat, Batman bursts in and begins fighting off the henchmen. Upon untying Andrea, Batman is smashed across the head by Reeves using Phantasm's claw before doing the same to Andrea. Reeves pulls off the unconscious Batman's mask and, realizing that Batman and Bruce Wayne, two men who had "put him through hell" are the same person, prepares to slit his throat, only to be kicked back by Andrea. Andrea dawns her Phantasm outfit again and Reeves madly lunges at her, only to find that he is attacking the costume, plunging off the balcony to his death.
Arthur Reeves is quite similar to his associate Mayor Hamitlon Hill where they both are concerned about their political capital as well as approval ratings as well as having a distaste towards Batman for breaking the law. Unlike Mayor Hill however, Reeves is more concerned about making advancements in his career as well as getting rich rather than the welfare of a city and is willing to associate himself with mobsters such as Salvatore Valestra, Chuckie Sol, and Buzz Bronski (it was strongly hinted that (Mayor Hill has met Reeves' employer Salvatore Valestra at some point in the past through a photograph Valestra has of him shaking hands with the mayor but it seems clear that Hill may have been unaware that Valestra was a mobster. Hill shows no traces of corruption and strongly values human life as when Hill objected to the Joker's plans to bomb an entire city once since there were people there. Hill was also even willing to pay a fortune to the Joker thinking he wanted to hold the city for ransom until he realized otherwise).
While Beaumont considered Reeves to be a trusted friend and advisor, Reeves was treacherous against his boss as he was willing to betray him to the mob, ruining Bruce Wayne's as well as Andrea Beaumont's lives. Reeves mocked Bruce Wayne at some point at a dinner party Bruce invited him about Bruce having bad luck with women and how Andrea left him. Later after Reeves was helping Andrea with her finances, Reeves then attempted to make advancements towards Andrea after mocking Bruce about it only for Andrea to politely decline (Reeves was unaware that Carl was dead after selling him out to Valestra).
Reeves is shown to be a quite vain, arrogant, selfish, and narcassistic young politician who, although seemingly in love with Andrea Beaumont, let her father get killed by a hitman who would later be the Joker. Reeves was not only corrupt and a puppet to the mob but was also quite nervous and anxious when his life would be threatened. For instance, he began to sweat and pant when the Joker was threatening his life, proving that he clearly was scared and desperate for his life. He would do anything to save himself and did not care about what would happen to others.
High-level intellect/Master lawyer/Expert investigator: Before becoming a member of the city council, Reeves was a lawyer for Carl Beaumont at his firm and a personal assistant of his. His ability to use the legal system to his advantage allowed Reeves to aid himself as well as others only if there something in it for him. In the Batman Adventure comics, Reeves was also a capable investigator as he was able to deduce Andrea Beaumont's identity as the Phantasm when he blamed her for his problems after being disfigured by the Joker.
Network: As a former city councilman, Reeves had multiple contacts to businesses, police departments, and government officials. As a member of the Valestra mob, Reeves had multiple contacts in the criminal underworlds as he was able to use them to find out who the Phantasm was and send multiple mercenaries after Bruce. In the Batman Adventure comics, Reeves was still shown his contacts in the underworld even after his corruption was exposed.
Expert hand-to-hand combatant/Expert Knife Wielder/Stealth: In the Batman Adventure comics, although he is not a martial artist similar to Bruce as well as Andrea, Reeves can fight vigilantes in unarmed combat as long as he has a weapon in his posession, such as a gun or a knife. Reeves was also shown to have excellent skills in stealth as he was able to ambush Bruce and Andrea at some point in the Batman Adventure comics.
While Arthur Reeves' mainstream comics counterpart was never the nicest individual (vehemently opposing to Batman's vigilantism), he was largely regarded as comic relief instead of a genuine villain. Up until his appearance in Batman: Mask of the Phantasm, after his initial debut, Reeves was featured as running for mayor on an anti-Batman platform, but would ruin his own campaign by publicizing hoaxed photos from Rupert Thorne which depicted Batman as a mob boss, leading Reeves to retire from politics in disgrace. His incarnation of the DC Animated Universe, however, is more selfish and arrogant who, despite his initial kindness, backstabbed his former boss in exchange for the necessary money to finance his political campaign despite possibly knowing Salvatore Valestra's intentions and ordered a manhunt against Batman without proofs that he was killing Valestra's mobsters just for the sake to not lose his money, making this version of the character far worse and darkest than his mainstream counterpart.
Ironically, in the comics, the candidate who ran for mayor against Reeves and ended up wining due Thorne's intervention was none other than Hamilton Hill, who was corrupt in comic book continuity and on Thorne's payroll, whereas the DCAU incarnation of Hill is never depicted as corrupt but rather as an effective law official, being represented as the contrary he was in the comics in a similar vein to Reeves. Coincidentally, Hart Bochner, the actor who voiced Arthur Reeves in the film, is the son of the late Lloyd Bochner, who voiced Mayor Hill in Batman: The Animated Series and The New Batman Adventures.
Despite meeting his ultimate fate in Batman Adventures, since the series is debatably non-canon to the DC Animated Universe, it is possible that Reeves was never "cured" of Joker's toxins, meaning he is still poisoned yet alive. As of the events of Batman Beyond, however, his status can't be determined.
Reeves closely resembles Harvey Dent, before his pre-disfiguration in "Two-Face". Unlike Dent however before his disfigurement, Reeves was a mob puppet while Dent was fighting to keep the city clean until Rupert Thorne shattered his life.