- "Two names, one goal. Black Mask terrifies the city, Roman Sionis rescues it."
- —Black Mask[src]
After the death of Roman's daughter, Circe, he decided to take revenge on the authorities and destroy the system. With the help of the hypnotist Enigma, he brainwashed Kate Kane into his new daughter, while Kate was presumed dead.
Roman eventually got into a confrontation against Bat Team. After one last final confrontation against Beth Kane, she sprayed the Joker's acid on his face, permanently welding his black skull mask to his face.
After Roman's identity as Black Mask was exposed to the public, he was arrested and sent to Arkham Asylum for his crimes.
At some point, Roman became the CEO of Janus Cosmetics and had a daughter, named Circe. Around 2016, Circe was assaulted by Ezra Castellanos, which led to her gouging his eyes out. She was then arrested by Crows Security and incarcerated at Arkham Asylum. In mid-2020, Circe was killed in the fire of Arkham that was set by Alice. Roman blamed the first Batwoman as she was in Arkham during the fire.
Leading the False Face Society
Meeting the new Batwoman
Roman ordered the gang to kill those involved in the murder, including a witness, Jordan Moore, but she was saved by Batwoman. He later ordered Angelique Martin to be captured, after learning that she wanted to leave the gang. In his hideout, he told Angelique that if she tried to leave the gang, she would die too.
After Batwoman showed up to save Angelique, she was knocked out and tied up. On the other side, Black Mask told the guy who went after Jordan that he failed and was out, before killing him using a fist. Batwoman asked him what the hell he was doing, he said it was an "H.R. matter" and asked if she was a "OSHA" and she replied that she was after Angelique.
Roman asked who she thought he was, with her replying that he is a sadistic drug lord. He then says he understands why she thinks so, but he was only trying to get rid of the Crows and bat vigilantes, after they arrested and killed Circe. He said he didn't need her help and told his henchman to start the saw, but then Sophie Moore came in and he ran away.
Needing a chemist
Upon Black Mask's command, the killers of Commissioner Forbes were terminated to assure their silence.
A week later, Black Mask kills a gang member because the gang member was in charge of distribution and distribution was constantly being interrupted by Batwoman, who declared war on him on television. Black Mask made an example of him in front of other False Face members. He told the others that the supply of the drug is too low for them to allow anyone to disrupt the operation. One of the gang members reminded Black Mask that he had kept secret the formula to Snakebite except for the two chemists, Ocean and Angelique Martin, with one gone and the other in jail.
In his civilian identity, Roman went to Crows Headquarters and told Jacob Kane that he found a container of Snakebite that one of his employees had and wanted it destroyed properly. Jacob was more than willing to help the client.
When Angelique was being moved into witness protection, Black Mask sent gang members to kill her transport guards and to capture the chemist.
Black Mask had Angelique brought before him and threatened to have her burned with acid and chemicals if she did not agree to help by making more Snakebite. He then sent caravans of drivers with high-speed vehicles to get the ingredients necessary for the process. He gave his drivers burner phones and sent alternating routes to his warehouses through them. If the driver took too long to reach the site or took a route not directed, as he had a drone observing, the driver was considered "burned" and he would not accept the product. One driver was burned when she was captured by Batwoman, causing Black Mask a slight delay.
Days later, Black Mask was at one of his warehouses when he found Sophie Moore lurking into his business; he captured her and had her bound. Just as he planned to kill her, Batwoman arrived and began a battle; Black Mask was able to hit the hero hard enough to make her mouth bleed. Knocking her down, he was about to shoot her but Sophie freed herself and injured him with a batarang; the two took his gun and overwhelmed him. They asked for the whereabouts of Angelique so Black Mask showed them a display where Angelique was being held at gunpoint. The gang leader told his minion to shoot the chemist if he was not freed, causing Sophie and Batwoman to comply and allowing him to leave.
Black Mask went to where Angelique was making more Snakebite. He decided that the product needed to be tested and asked Angelique to try it, but she said that she was clean now and would not indulge. Thinking that she was being rebellious, Black Mask insisted, to the point of almost injecting her himself. Angelique begged him to stop and explained that she learned the formula of the drug through assisting Ocean and by observation, not formal training. Black Mask realized that the drug was unpredictable and could cause death, instead of euphoria, prompting him to need his master chemist.
After six weeks of therapy and hypnosis, Kate Kane has been transformed into a replica of Circe Sionis. Black Mask removes his mask in front of Enigma so that Kate/Circe will not be confused and will know that "her father" is beside her. He tells "Circe" that she wears a mask because her face was burned in the fire at Arkham.
Later, Black Mask has Ocean kidnapped and brought, with Angelique, to a warehouse so that they can make Snakebite. Black Mask has a gang member video-record the process and tells the gang member to kill the chemists when they are finished. Soon afterwards, "Circe" brings Alice to the mansion because Alice assisted Batwoman in helping Ocean and Angelique escape the warehouse. Originally, Black Mask is annoyed and tells "Circe" to kill Alice, but, before "Circe" can give the kill-shot, Black Mask changes his mind, saying to his masked "daughter" that he has a job for Alice.
Working with Alice
Black Mask tortured Alice to discover the identity of the new Batwoman, but it failed, because she escaped confinement and tricked "Circe" into revealing Black Mask's civilian identity. Alice persuaded Roman not to kill her but to allow her to earn her life by making "Circe" a new face with Alice's "mask technology" and maintaining its composure. When Roman saw the face of "Circe" restored, he was overwhelmed with happiness and hugged "his daughter"; he rewarded Alice with her freedom, but promised to remove her tongue, if she revealed his secret identity or what she had done for him. Roman could not understand why Alice, who continually stared at "Circe", was hesitating to leave, so Roman asked two gang members to escort Alice out. Alice left on her own.
Later, since Ocean and Angelique were not available, Roman hired a new chemist and allowed a blue version of Snakebite to be made.
Brainwashing Kate Kane
Roman later planned to reveal a new brand of make-up titled "Resurrection" as his official attempt to re-introduce his "daughter" back into high society. Upon her capture by Alice and Jacob, Roman had the False Face Society track them down. Roman was later with Safiyah Sohail when he informed her of 'Circe's' abduction, to which Sohail scolded him for. She subsequently revealed that Alice is Beth Kane, and that his "daughter" is her sister. Realizing this, Roman later revealed Alice's identity to the public, causing Jacob to be arrested, and reunited with "Circe" after having her retrieved from the Bat Team.
Roman and Safiyah induced "Circe" to impersonate Kate and enter the Batcave; to steal Venom, Clayface's mud, Killer Croc's tooth, Mad Hatter’s top hat, Penguin's umbrella, Joker's acid flower and a cutting of Poison Ivy's vines.
Terrorizing Gotham and incarceration
- "Good evening, fair citizens of Gotham City. Black Mask here. I ask you to look past this ghoulish veil and realize it is not the affectation of a madman but rather the necessary concealment of an altruist, so...how does one fix a broken city? Well, I've heard the phrase 'Defund the Police' bandied about. Please. The GCPD can't afford the hole in its doughnut. Well, what about Arkham Asylum, that house of horrors that you fund with your tax dollars, or Blackgate Prison, too violent for Jacob Kane, loving father of lunatic at large Alice of Wonderland? Well, how about Gotham City Hall then or the judges or the D.A. or the banks, all chock full of predatory degenerates so crooked they've got to screw their pants on in the morning? And don't even get me started on Batwoman, operating without checks or balances, leaving the collateral damage of an untold number of innocents in her wake. Why are we allowing these self-serving bandits to dictate to us what the terms fair and just mean? We should be dictating these terms to them, so I'm asking you to join me for an evening of anarchy. Help me raze every single one of these moldering institutions to their foundations. I've dropped masks at a dozen street corners. Stand up, strap one on, become your own vigilante, and when the dust finally settles over our failed system, well, Black Mask will still be standing, ready to lead you to your liberation because you know what they say about power, huh? Use it...or lose it."
- —Black Mask broadcasts to the citizens of Gotham City.
As Black Mask, Roman incited anarchy in Gotham and made plans to have one of his subordinates take on the mask to be used a sacrificial lamb, in which Roman would kill Black Mask and be lauded as Gotham's savior. Black Mask assumes control over Gotham's TV wireless transmissions, approaching Gotham residents to wear their own Black Masks and destroy the frameworks of mistreatment in Gotham.
Black Mask infuses Russell Tavaroff with a portion of Bane's Venom with Snakebite. While Tavaroff is being infused, Black Mask discloses to Circe his arrangement: cause disorder, and afterward coordinate having another person wear the Black Mask so Roman Sionis can freely execute him and be delegated the legend of the city. When Tavaroff flatlines, he is thrown out by Black Mask.
When Alice and Batwoman invade his hideout, "Circe" fights Batwoman and Sionis battles Alice, and contends that she's never going to be a full miscreant. Alice then retorted that Joker was a great villain and sprayed the Joker's acid on Roman's face before slamming his mask onto it, welding it to his face. After Roman's identity as Black Mask was exposed to the public, he was arrested and sent to Arkham Asylum for his crimes, where he continually muttered, "Janus" to himself.
- "They are scared to death of the criminal element lurking behind masks, but I'm not here to beg for help today. I'm here to offer it. To the law enforcement in charge of protecting us, what can we do? How can we help you? Because enough is enough."
- —Roman Sionis[src]
In public, Roman puts up the façade of a legitimate businessman and a white knight dedicated to helping the legal system.After Roman's identity as Black Mask was exposed to the public and that his skull mask was permanently welded onto his face, he appears to have gone completely insane.
- "You're a sadistic drug lord."
- "...Okay I can see why you might think that. But it's Gotham that's sadistic, not me and they say the best way to change the system, is from within."
- —Batwoman and Black Mask[src]
- High-level intellect/Great business acumen/Master tactician/Leader: Roman is highly capable of leading the False Face Society from behind the scenes and in person. He created the spread of the Snakebite drug across Gotham City. He orchestrated the bombing of Kate Kane's plane, kidnapping her, and brainwashing her into his deceased daughter's identity. He manipulated events to force the Crows organization to disband including gaining control over corrupt GCPD officers to arrest Jacob Kane and Ryan Wilder.
- Master of deception/Manipulator: Roman is highly skilled at deceiving and manipulating others to his advantage. He is able to hide his identity and activities as Black Mask, putting on a facade of a white knight willing to help the legal system. He was able convince the former Crows agents to join him. including the initially reactant Russell Tavaroff.
- Expert hand-to-hand combatant: Roman is a skilled hand-to-hand combatant as he was able to disarm and incapacitate Sophie Moore with a single kick to her lower back. Roman was able to fight Ryan (under the persona of Batwoman) and eventually gain the upper hand on her, even causing her mouth to bleed, though he only managed to gain the upper hand against the bat vigilante in their first/only confrontation by using dirty tactics. When Sophie joined the fight, he was able to briefly fight on until he was overwhelmed by the two of them. He was able to overpower Beth Kane, causing her to spit blood from just a single punch, although it was likely that he was using dirty tactics in their first/only confrontation.
- Expert marksman: Roman is quite proficient in the use of firearms, particularly handguns. He was able to shoot two handguns simultaneously at Ryan and Alice.
- Expert interrogator/Torturer: Roman is proficient in interrogating and torture to get information or to get others to do his bidding.
- Intimidation: Roman uses a black skull mask and his status as a crime lord to intimidate other individuals. However, he is unable to intimidate Beth, Jacob and Ryan respectively; not only due to the fact that they are aware of Roman's secret identity as Black Mask, but they also know what a coward he truly is.
- Stealth: Roman was able to ambush Sophie. Talking at her from the shadows before appearing behind her.
- High tolerance for pain: Roman was able to pull a batarang out of his back with little discomfort and despite being stabbed through the hand with a karambit, still maintained the lie that "Circe" was having an episode.
- Acrobatics: Although Roman is past his prime, he is surprisingly agile. He faulted over a table with both hands in his fight with Batwoman.
- Network: As a businessman and a crime lord, Roman has many contacts in the criminal world and in high society.
- "It's a symbol of liberation from people like you, people who think they'll never be held accountable as long as they pretend that what they do is justice."
- —Black Mask to Batwoman[src]
- Black Mask mask: Roman wears a black skull mask in order to conceal his identity when operating as Black Mask. Later, Roman's mask is permanently welded onto his face; due to Beth Kane sprayed the Joker's acid onto his face.
- "You should really consider bringing a gun to a gunfight."
- —Black Mask
- Handgun: Roman uses this handgun as his sidearm when operating as Black Mask. He later wielded two of these guns during his confrontation with Ryan and Alice.
Behind the scenes
- In the DC comics, Black Mask is a crime lord in Gotham City, the leader of the False Face Society and one of Batman's longtime enemies. He debuted in Batman #386 (August, 1985).
- Roman having his mask welded onto his face; due to Alice's use of the Joker's acid flower is adapted from Batman #387, where his comic-counterpart's mask ends up being permanently charred into his skin after falling into a fire. In addition, after this, Black Mask ends up being taken to Arkham Asylum.
- Roman served as one of the main antagonists of the second season of , alongside Safiyah Sohail.
- Roman is one of two antagonists with Safiyah, (except Alice who redeems herself to become Beth Kane again), to discover the identities of the two Batwomen. But he becomes completely insane after sprayed by The Joker's acid and Safiyah falls in comatose by Beth Kane, protecting the secret of Kate and Ryan.
- he is the only main antagonist of batwoman who did not become a villain directly or indirectly because of the joker