Boris (Russian: Борис; Japanese: ボリス Borisu) is Balalaika's second-in-command in the Thai branch of Hotel Moscow.

Boris is a tall, broad Russian man with pale skin and short black hair. He can be easily identified by the large scar running from the right side of his forehead to his left cheek. Additionally, he wears a dark green suit over a black turtleneck shirt and dark green pants. In the manga, his eye sockets are frequently shadowed by his brow ridge. He carries an MP-444 Bagira pistol for a weapon.

Boris is reserved and follows Balalaika with unconditional loyalty. Despite being a hardened and intelligent soldier, he is empathetic, especially compared to Balalaika and other Roanapur residents; he found it hard to watch when his boss let a child like Hänsel spend his last moments in pain despite what the twins did to one of his comrades. He occasionally mixes Russian words into his speech, and he has a noticeably deep voice when he speaks.

Like Balalaika, Boris had served in the former Soviet Airborne Forces during the Soviet invasion of Afghanistan. She still refers to him as "Sergeant" (Russian: сержант) rather than by his name, showing that he was her former platoon sergeant; likewise Boris always refers to Balalaika as "Captain" (Russian: капитан). Before his wartime service, his first military training began at a Soviet Airborne Forces academy in Ryazan, Russian SFSR, USSR. In 1987, Boris had not received the scar on his face yet, indicating that he had not been injured until sometime near the end of his service. He continued his loyalty to Balalaika at a graveyard of their comrades when she decided to first join Hotel Moscow. He is very loyal and protective of Balalaika and often worries for her safety when she decides to fight in the field. Furthermore, Boris is the only member of Hotel Moscow who frequently accompanies Balalaika in her office room at the Bougainvillea Trade Company building. Wherever Balalaika travels, he respectively takes off and puts on her military coat around her shoulders whenever she enters and leaves any place.

Boris accompanied Balalaika in her office when she called Dutch and confirmed that the Lagoon Company successfully stole an Asahi Heavy Industrial Co. disk containing nuclear weapon blueprints. Later when Dutch returned to Roanapur to give her the disk, he called her again. Boris stood guard with other Hotel Moscow members in Balalaika's office as she had a Chinese man interrogated, who was forced to inform Dutch over the phone about the mercenary company that Asahi Industries hired to hunt down the Lagoon crew in the city. After the Chinese man gave the information, Boris and the other men shot the man as Balalaika calmly covered her ears. Soon, he accompanied Balalaika to Palawan Island to meet up with Kageyama after the Lagoon Company defeated the Extra Order mercenaries and successfully brought the disk to Balalaika. After the trade, Boris drove his boss back to the airport, but not before she commended Rock for helping the Lagoon crew succeed.

When Chen blabbed about his plan to assassinate the Lagoon crew to lots of people in Roanapur, Balalaika got word of his plans, so she, Boris and other Hotel Moscow members went to Chen's place and confronted him before he could flee the city. After the Russians tortured and tied up Chen to a chair, Boris stood by outside with fellow Hotel Moscow members as Balalaika called Dutch to imply that she would deal with Chen, detonating a bomb inside the Chinese gangster's residence. Sometime later in the anime, it was shown that Boris and other Hotel Moscow gangsters also captured and executed Donnie Yen for abetting Chen's failed plan.

During Garcia Lovelace's initial imprisonment by Lagoon Company (who was shipping the boy), Dutch asked Balalaika for intel on their client, the Manisarera Cartel. Soon, Balalaika gathered the info in her office regarding the Lovelace family, and Boris listened to her mention the family history. When she asked Boris to look at Roberta's eyes in a photo she took with the Lovelace family, he saw that she had the eyes of a soldier. The same night, Roberta began a rampage at the Yellow Flag in her attempt to rescue Garcia, gaining the attention of Hotel Moscow. Accordingly, Balalaika remarked that she owed a favor to Dutch, so she had Boris help her organize the Vysotniki to save the Lagoon Company from being killed by Roberta.

As Revy and Roberta started a firefight with each other, Boris and several snipers surrounded the two women and forcibly disarmed them. Although Balalaika informed the maid that Hotel Moscow destroyed the Manisarera Cartel's base in Venezuela, she and Revy still wanted to fight. Hours later after Revy and Roberta settled the fight ending in a draw, Balalaika ordered Boris to drive the maid back to the airport so that she and Garcia could return to their home in Venezuela.

Because of the sudden murders of six Hotel Moscow affiliates, Boris called the Lagoon Company office to inform Rock that Balalaika had to cancel her meeting with the Lagoon Company. Afterward, he attended Mister Chang's emergency Council meeting in private to ascertain which mafia did the killings of various gangsters around town. As Verrocchio insulted Balalaika, Boris showed visible disdain toward his comments. Once Balalaika proclaimed that she had no intention of friendship between the mafias due to the recent murders, Boris saw that she was ready to leave and helped her don her military coat. When two more members of Hotel Moscow, Corporal Menshov and Private First Class Sakharov, were murdered by the twins Hänsel and Gretel, Chief Watsap of the Roanapur City Police allowed Boris and Balalaika to investigate the crime scene at the Caribbean Bar, where the two Russian men were murdered. Upon listening to Watsap's recollection of a sole survivor's testimony, the two Russians left the scene. Boris sat in the back seat of a car with Balalaika, who told him that she despised Watsap's character and that she felt she did not account for something. Boris responded that even Menshov and Sakharov were blindsided by the assassins being children. Balalaika stated that the murderers would pay with blood, telling Boris to set up an investigative team outside of their organization. Agreeing to her order and trying to console her, he assured her that Menshov and Sakharov were nonetheless prepared to die in battle when they pledged their loyalty to her.

Later that night, Balalaika called Rock to see if he recognized the phrases "soră mea" and "buona sera" that the twins used. The ex-salaryman soon realized that the former of the phrases was Romanian and relayed that fact to Balalaika, who told Boris. He remarked that he remembered picking up some Romanian words from Romanian troops in Kabul during the Soviet-Afghan War, admitting that he was embarrassed that he could not recognize the terms. Reminding him that she could not remember either, Balalaika replied that their forgetfulness was just part of growing old. In deep thought, she asked if Rowan "Jackpot" Pigeons distributed black market videos, which Boris confirmed, so she recovered all the child sexual exploitation tapes involving Romanians that Rowan had. Eventually after viewing 250 videos, Balalaika spotted the twins in one of the films, finding out their stage names in the show as well as their appearance.

Following a discreet meeting with Mister Chang, Balalaika called Boris to confirm that the Hong Kong Triad agreed to an alliance with Hotel Moscow to stop the twins, advising him to gather all their men for a combat mission like their former military days. Later that night, Boris called all of their troops into one room, ordering them to listen to Balalaika. She gave a quick speech about the brotherhood they shared with Menshov and Sakharov, confidently saying that the souls of their fallen comrades would transform their guns into a goddess of revenge. As the Vysotniki spread throughout Roanapur on rooftops on particular streets, Boris stayed in-person with Balalaika at a fountain and had all unit commanders report back to him. As the twins began to run away and were flanked onto a specific path, he relayed the troops' reports to her, but they soon heard a gunshot in an area that the troops had not covered yet.

In minutes, Jodorowsky reported back to Balalaika, who took control of communications from Boris, concerning the twins' location. At that point, Boris bid good luck to Balalaika and left so that she could wait for Hänsel to be lured to her for his death. The next morning as the operation continued, he waited with the snipers Lazar and Daniil on a distant rooftop as they watched Balalaika sit and confront Hänsel. Boris silently observed as the snipers shot Hänsel's arm and leg while Balalaika watched the boy bleed to death. After Hänsel finished crying and died, she radioed to Boris to say she was done, and he confessed that the ordeal was bone-chilling. Meanwhile, Dutch was shipping Gretel out of Roanapur, and Boris later waited at the front door of Balalaika's room while she called Dutch to sternly affirm that Gretel would not escape alive. Finishing the call, she ordered him to get a hold of Elroy so that she could pay him to kill Gretel as insurance.

Sometime later, Boris traveled Balalaika when she visited Japan to help the Japanese branch of the Russian mafia gain influence in the country. He first accompanied her as she had a meeting with Tsugio Bandō of the Washimine Group to ally together against the Kōsa Council. After the meeting, Boris went with her to a restaurant to talk with Vasili Laptev. He asked her if she wanted him to get her some Russian tea, but she replied that she did not want to make a fuss, asking him in turn if he wanted some toast, but he politely declined. As Balalaika and Laptev ate their food, Boris summarized the Vysotniki's recent attacks on the Kōsa Council, reporting many successful kills without any casualties or fatalities for the Vysotniki. He added that the Washimine Group transcribed the Kōsa Council's wireless communications, so she ordered him to have Rock provide her with the translation as soon as possible. Boris stood by as the two exchanged insults, with Balalaika slamming Laptev against the table and leaving afterward.

Later, he attended her second meeting with Tsugio Bandō. When Bandō rejected her plan to kidnap the Kōsa Council's head, Balalaika was amused and rhetorically asked Boris if he heard Bandō's answer. After exiting the meeting and seeing Yoshida having to restrain Chaka from beating up Rock, he agreed with Balalaika's comment that the yakuza lacked their military discipline. At the previously visited restaurant, the two Russians met up with Revy and Rock, with Boris again briefing Balalaika on the Kōsa Council, who had surveillance on them increased by the police. He asked his captain if they needed to consult Laptev before moving forward, and she calmly assured him that she had permission from Slevinin to cause chaos. After she murdered Bandō and Ginji Matsuzaki assassinated Laptev, Balalaika asked Boris about the news at their hotel room, with the latter confirming that he heard about it. As he smiled about Laptev's elimination, she declared that Monk Burgashvili would take his place as Hotel Moscow's Japanese branch leader. Much later, on the same night, Rock and Revy helped save Yukio Washimine from Chaka. Meanwhile, Boris ordered his men to prepare their campaign to destroy the Washimine Group. The subsequent morning, when he could not contact Rock at his hotel room, he wondered what he was up to, but Balalaika replied that it did not matter. In the Marya Zaleska war room, the Russians then commenced the anti-Washimine operation. As the assassinations of Washimine enforcers continued, Boris received reports from his men about the killings of the bases and gangsters like Shigeru Itō, Kudō, and Takeshi Ogami. The next day, Rock reconvened with Balalaika and Boris in an underground parking lot, and he demanded that Balalaika wage war with the Kōsa Council instead of the Washimine Group, surprising Revy. When Rock tried to reason that the Washimine Group was already weak enough, Balalaika grabbed him and pointed her pistol at his head. In response, Revy drew a gun on her and on Boris, who drew his gun on Revy in turn. In the standoff, Rock stated that it was his hobby to save people, making Balalaika laugh. As Boris showed slight confusion concerning Balalaika's laughter, the Russian leader withdrew her gun, which made him withdraw his gun too.

Later, in the anime only, when Yukio and Ginji committed a bank robbery, they framed Hotel Moscow by using a van designed to mimic one of the Russian vans. Minutes after the robbery, Japanese police cars chased the van that Jodorowsky was driving, confusing him. He reported the situation to Boris, who told him to lose the cops. Accordingly, Jodorowsky tossed a smoke grenade out the driver's window, evading the police who were blinded by the smoke. Afterward, Boris told Balalaika that they would get rid of their van due to Yukio's countermeasure, and he stood silently as Balalaika claimed that they needed to exponentially crush Yukio.

Eventually, Boris and Balalaika waited inside the Kōsa Council headquarters to converse with Masami Kōsa. While Balalaika listened to Rock's request, Boris called for a car to pick them up from the meeting. He then interrupted the two to say that Masami was ready. Sitting down next to his captain, Boris stayed silent as Masami agreed to their terms to team up against the Washimine Group. Still hesitant about the alliance, Balalaika asked Masami's bodyguard to show her his weapon, which she tossed to Boris. She then asked for his backup weapon, a small Accu-Tek pistol, and she insulted the small size of the pistol, greatly shocking Boris. When she turned the pistol on the Japanese men, Boris aided her and killed Masami, Morozumi, and the other Kōsa gangsters in the headquarters. When the police heard the gunshots and tried to barge into the residence, Boris wondered how they would report the situation to Pyotr Slevinin, but Balalaika confidently answered that she followed Pyotr's orders through and through. Seeing that they were done with their mission, she ordered him to throw away Morozumi's pistol.

Exiting the residence, Boris told Balalaika that they were good for time, so she ordered Rock to inform Yukio about the former woman's ultimatum, and she advised the police officers Yasuzawa and Ishiguro to make way. A Russian Federation embassy car arrived, with V.N. Valizhinov allowing them to travel with him under the guise of diplomatic immunity. The two Russians went back to their ship which they had used to travel to Japan from Roanapur. In the end, Yukio and Ginji died, finally ending the campaign against the Washimine Group.

When it was confirmed that Roberta returned to Roanapur, Mister Chang called for a Council meeting between Roanapur's crime lords, including Balalaika, at The Golden Swingin Night Club. Boris informed Balalaika of the meeting, adding that Chang was likely going to tell them important information about the maid. Balalaika wondered who Roberta's enemy was, and Boris guessed that the people responsible for killing Diego Lovelace could not have been local forces or a political party since the latter would not need refuge in Roanapur, adding that it was likely a well-trained third party. That night, Boris attended the meeting as Balalaika's right-hand man, finding out that U.S. Army soldiers were Roberta's target. Balalaika added that she wanted the U.S. Army out of Roanapur since the Americans would crush the drug trade if they stayed in the city.

Sometime after the meeting, Balalaika decided to deploy the Vysotniki to stave off Shane Caxton's soldiers as well using the chaos as an opportunity to take territory away from Mister Chang. Once all the teams got into position and prepared a kill zone, Boris informed Balalaika that the men were ready. In exchange for not interfering in Roanapur and Hotel Moscow's affairs for that matter and preventing Roberta from killing them, the Vysotniki offered to cover the rooftops and give cover to the U.S. Army to allow them to leave. Boris accompanied Balalaika as they kept track of Roberta's movements, and Balalaika spoke to Caxton over the radio to support him and later bid him goodbye. In the anime, as Roberta chased the escaping U.S troops, Boris stood by while the Vysotniki shot at her motorcycle with all their firepower, preventing the maid from chasing the troops further. Caxton's squad was able to escape Roberta and leave by traveling on the Lagoon Company's boat, putting an end to the Vysotniki's mission. In the manga, as the Vysotniki contained and prevented Roberta from leaving an alleyway to chase the Americans, Boris ordered his men in Russian to position themselves for giving a gun salute to Caxton as Grey Fox left Roanapur.

When Black men were being murdered across Roanapur, of whom the majority were contracted under Hotel Moscow, Mister Chang hosted another Council meeting between the crime lords to share information in order to deduce who committed the murders. Balalaika of course attended, and Boris went to the meeting as well and took off her jacket as she sat down to talk. Later, after Rock found out the identity of the attackers and also had intel on them from the traitor Le Majeur, he went to the Bougainvillea Trade Company building to speak to Balalaika about his plan to use Dutch as bait to lure the Frenchwomen into the open. Boris stood by as she listened to his plan, and she agreed to mobilize the Vysotniki three days later to ambush the women. On that night, Boris waited inside the nightclub with a rifle as the Frenchwomen entered. As soon as Dutch turned around, Balalaika revealed herself, so Boris and his men began shooting at and cornering the Frenchwomen, eventually killing them all after sweeping the building. Afterwards, the next Council meeting to discuss Le Majeur's fate ended with her staying alive, so Boris helped Balalaika don her military jacket, and he left with her.

While Balalaika was concluding her meeting with Rock and Revy, Boris peered into her office and informed her that it was almost time for her next meeting with Varenkov and Vasily Krivchenko. Accordingly, the two pirates announced their leave and Balalaika commenced her subsequent meeting. Some day later, after the next Council meeting ended on a bad note due to Gris el Tigres affirming that he would kill Krivchenko, Boris waited in the car as Balalaika told Varenkov that she would put Krivchenko under her protection. On the way back to headquarters, Balalaika relayed to Boris that they would set up a strategy meeting when they returned. Soon, the forces of Los Soldados attacked Hotel Moscow-owned businesses, so Boris took charge of listening to and relaying communications to their counterattack forces. When four businesses were simultaneously hit, he informed his captain that explosives were rumored to be carried inside by guests in exchange for a payoff, claryifing that eight lower organization Russians were killed but no Vysotniki casualties occurred. Balalaika wondered why the guests were not searched, to which the sergeant surmised that they could not be that thorough for their non-casino businesses.

In response to learning that Los Eses attacked go-go bars with lax security, she asked if there was any good news at least. Boris merely stated that the assailants stopped their pursuit while squads Perun and Volos were in pursuit. However, the two squads reported to the sergeant in real-time that they were cut off by a semi-truck from pursuing, and the advance team returned to the headquarters. Balalaika greeted her men, with one of them giving her a DVD intentionally left behind and addressed to her. Accordingly, the disk was played, and Boris and co. watched the announcement by Gris affirming that he would only cease attacking if they brought Krivchenko to him to be killed. After the video finished, the sergeant admitted the Mexican soldiers' attacks were perfectly executed. Balalaika ordered him not to spread out their personnel any further and wondered if they could identify where Gris filmed the video from the background. Though saying it would be difficult, the sergeant confirmed it could be done.

A short period after these attacks, Boris relayed to his captain that they had not been able to track the enemy group they lost at Chalquam Street. The sergeant added that the Roanapur City Police sealed off six locations and set up checkpoints but had not spotted any of the gangsters, assuring Balalaika they would keep looking. As they discussed the enemy splitting into three trails in the red-light districts without leaving a trace, Boris wondered if Los Soldados had their base outside the surrounding city. Recalling that they had had eight years of peace thus far, Balalaika agreed with his recommendation that they needed to seek out the Council's help to prevent war breaking out. Boris declared they might have to resort to the old days of solving things with bullets, a possibility with which Balalaika concurred.

A couple of days later when Fernando Lobos was executed by Gris, his severed head was dropped off in front of the Bougainvillea Trade Company office. Upon discovering that it was Lobos's head and not a bomb as initially believed, Boris and his captain grimaced at the sight.

In the first light novel Shaitane Badi, Boris waited completely still in Balalaika's office as she spoke with Dutch and then frustratingly spoke with Tatiana Yakovleva. After Yakovleva had left, Boris commended Balalaika for showing restraint, but he politely added that the Nefrit 's involvement in the attack on Chang was cause for alarm, also recommending that she should call Dutch to be discreet just in case. Balalaika agreed about the caution but assured the sergeant that Dutch was a man who was always careful. As Balalaika talked to Boris about the possibility of the culprit being a Vysotnik, Boris had the same thought as her when she uttered that the sniper was likely a fellow ex-Spetsnaz like them, given that the assassin knew how to calculate sniping in high winds. Boris in turn uttered the name Junior Sergeant Stanislav Kandinsky, also remarking that Stanislav had been dead for years, with Balalaika responding that she and Boris had also been dead for years.

Much later after Balalaika had killed Stanislav and Yakovleva's other hired mercenaries got killed, Yakovleva tried to flee Roanapur, but Boris and his driver blockaded her path and forced her car to crash into theirs. As Yakovleva wondered what had just happened, he smashed his arm through the driver window and grabbed her out into a Mercedez-Benz's backseat. Getting into the passenger seat, Boris told the driver to go as he shoved a cellphone into Yakovleva's face. On the other end of the call, Balalaika taunted Yakovleva that she called her bluff and had no more time to waste with Yakovleva. After the phone call finished, Boris and the driver brought her to Don Mueang International Airport and flew with her to Narita International Airport, where they stole all her money and took her gold teeth, killing her and putting her corpse in a women's bathroom stall at the airport. Late at night on another day, when Balalaika finished a call with Vasili Laptev to mock and threaten him, she sat in her office and prepared a cigar, prompting Boris to prepare a match to light her cigar.

Boris makes a cameo appearance in Volume 4 of Dismemberment Galore! The Gore Gore Girl when he stood near Balalaika when she visited Sawyer the Cleaner to discuss a treasure key, and he guided Balalaika into her car.

Boris accompanied Balalaika through town as they searched for two criminals who killed a Hotel Moscow drug dealer. Near the Roanapur Public Cemetery, the two criminals attempted to flee the area after being confronted by Martin. However, Boris and Balalaika were at the scene by chance and accordingly fired a barrage of bullets at the enemy car before they almost ran over a stray cat. As soon as the car crashed and the two criminals died, Boris picked up the unharmed cat and examined the vehicle. He asked his captain what they would do next, and she ordered Boris to have a third party deal with the criminals' corpses. As a result, he arranged for the corpses to be disposed of by Sawyer.

Борис